diff --git a/README.en-US.md b/README.en-US.md
index 872e206..1096c23 100644
--- a/README.en-US.md
+++ b/README.en-US.md
@@ -12,7 +12,7 @@
 
 A GitHub Action that easily helps you automatically manage issues
 
-[Online documentation](https://actions-cool.github.io/issues-helper) | [Changelog](https://github.com/actions-cool/issues-helper/blob/main/docs/log.md)
+[Online documentation](https://actions-cool.github.io/issues-helper) | [Changelog](https://github.com/actions-cool/issues-helper/blob/main/changelog.md)
 
 ## 😎 Why use GitHub Action?
 
@@ -34,6 +34,7 @@ When the following list does not have the features you want, you can submit it i
   - [`create-issue`](#create-issue)
   - [`delete-comment`](#delete-comment)
   - [`lock-issue`](#lock-issue)
+  - [`mark-duplicate`](#mark-duplicate)
   - [`open-issue`](#open-issue)
   - [`remove-assignees`](#remove-assignees)
   - [`remove-labels`](#remove-labels)
@@ -294,6 +295,39 @@ jobs:
 
 ⏫ [Back to list](#List)
 
+#### `mark-duplicate`
+
+Quickly mark duplicate issue.
+
+```yml
+name: Issue Mark Duplicate
+
+on:
+  issue_comment:
+    types: [created, edited]
+
+jobs:
+  mark-duplicate:
+    runs-on: ubuntu-latest
+    steps:
+      - name: mark-duplicate
+        uses: actions-cool/issues-helper@v1.5
+        with:
+          actions: 'mark-duplicate'
+          token: ${{ secrets.GITHUB_TOKEN }}
+```
+
+| Param | Desc  | Type | Required | Version |
+| -- | -- | -- | -- | -- |
+| actions | Action type | string | ✔ | v1.5 |
+| token | [Token explain](#token) | string | ✔ | v1.5 |
+| duplicate-command | Operation command, default is `/d` | string | ✖ | v1.5 |
+| duplicate-labels | Add additional labels to this issue | string | ✖ | v1.5 |
+| labels | Replace the labels of the issue | string | ✖ | v1.5 |
+| contents | Add [reaction](#reactions-types) for this comment | string | ✖ | v1.5 |
+
+⏫ [返回列表](#列-表)
+
 #### `open-issue`
 
 Open the specified issue.
diff --git a/README.md b/README.md
index 8f10b71..4d67a96 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@
 
 一个轻松帮你自动管理 issues 的 GitHub Action
 
-[在线文档](https://actions-cool.github.io/issues-helper/) | [更新日志](https://github.com/actions-cool/issues-helper/blob/main/docs/log.md)
+[在线文档](https://actions-cool.github.io/issues-helper/) | [更新日志](https://github.com/actions-cool/issues-helper/blob/main/changelog.md)
 
 ## 😎 为什么用 GitHub Action？
 
@@ -34,6 +34,7 @@
   - [`create-issue`](#create-issue)
   - [`delete-comment`](#delete-comment)
   - [`lock-issue`](#lock-issue)
+  - [`mark-duplicate`](#mark-duplicate)
   - [`open-issue`](#open-issue)
   - [`remove-assignees`](#remove-assignees)
   - [`remove-labels`](#remove-labels)
@@ -294,6 +295,39 @@ jobs:
 
 ⏫ [返回列表](#列-表)
 
+#### `mark-duplicate`
+
+快捷标记重复问题。
+
+```yml
+name: Issue Mark Duplicate
+
+on:
+  issue_comment:
+    types: [created, edited]
+
+jobs:
+  mark-duplicate:
+    runs-on: ubuntu-latest
+    steps:
+      - name: mark-duplicate
+        uses: actions-cool/issues-helper@v1.5
+        with:
+          actions: 'mark-duplicate'
+          token: ${{ secrets.GITHUB_TOKEN }}
+```
+
+| 参数 | 描述 | 类型 | 必填 | 版本 |
+| -- | -- | -- | -- | -- |
+| actions | 操作类型 | string | ✔ | v1.5 |
+| token | [token 说明](#token) | string | ✔ | v1.5 |
+| duplicate-command | 操作命令，默认为 `/d` | string | ✖ | v1.5 |
+| duplicate-labels | 为该 issue 额外增加 labels | string | ✖ | v1.5 |
+| labels | 替换该 issue 的 labels | string | ✖ | v1.5 |
+| contents | 为该评论的增加 [reaction](#reactions-types) | string | ✖ | v1.5 |
+
+⏫ [返回列表](#列-表)
+
 #### `open-issue`
 
 打开指定 issue。
diff --git a/action.yml b/action.yml
index 43804d3..caa3064 100644
--- a/action.yml
+++ b/action.yml
@@ -52,6 +52,10 @@ inputs:
     description: 'Query use'
   inactive-label:
     description: 'Issue label set use'
+  duplicate-command:
+    description: 'For mark-duplicate'
+  duplicate-labels:
+    description: 'For mark-duplicate add labels'
 outputs:
   issue-number:
     description: 'Create Issue Number'
diff --git a/docs/log.md b/changelog.md
similarity index 81%
rename from docs/log.md
rename to changelog.md
index 10a2ffb..eadf3f8 100644
--- a/docs/log.md
+++ b/changelog.md
@@ -1,3 +1,9 @@
+## v1.5
+
+`2020.12.30`
+
+- feat: add `mark-duplicate`. [#23](https://github.com/actions-cool/issues-helper/pull/23)
+
 ## v1.4
 
 `2020.12.29`
diff --git a/dist/index.js b/dist/index.js
index 5609605..3634a65 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -6286,6 +6286,8 @@ const octokit = new Octokit({ auth: `token ${token}` });
 const contents = core.getInput("contents");
 const issueContents = core.getInput("issue-contents");
 
+const context = github.context;
+
 async function doAddAssignees (owner, repo, issueNumber, assignees) {
   await octokit.issues.addAssignees({
     owner,
@@ -6400,6 +6402,32 @@ async function doLockIssue (owner, repo, issueNumber) {
   core.info(`Actions: [lock-issue][${issueNumber}] success!`);
 };
 
+async function doMarkDuplicate (owner, repo, labels) {
+  if (context.eventName != 'issue_comment') {
+    core.info(`This actions only support on 'issue_comment'!`);
+    return false;
+  }
+  const duplicateCommand = core.getInput("duplicate-command") || '/d';
+  const duplicateLabels = core.getInput("duplicate-labels");
+  
+  const commentId = context.payload.comment.id;
+  const commentBody = context.payload.comment.body;
+  const issueNumber = context.payload.issue.number;
+
+  if (commentBody.startsWith(duplicateCommand) && commentBody.split(' ')[0] == duplicateCommand) {
+    const nextBody = commentBody.replace(duplicateCommand, 'Duplicate of');
+    await doUpdateComment(owner, repo, commentId, nextBody, 'replace', true);
+    if (duplicateLabels) {
+      await doAddLabels(owner, repo, issueNumber, duplicateLabels);
+    }
+    if (labels) {
+      await doSetLabels(owner, repo, issueNumber, labels);
+    }
+  } else {
+    core.info(`This comment body should start whith 'duplicate-command'`);
+  }
+};
+
 async function doOpenIssue (owner, repo, issueNumber) {
   await octokit.issues.update({
     owner,
@@ -6466,7 +6494,8 @@ async function doUpdateComment (
   repo,
   commentId,
   body,
-  updateMode
+  updateMode,
+  ifUpdateBody,
 ) {
   const comment = await octokit.issues.getComment({
     owner,
@@ -6481,7 +6510,7 @@ async function doUpdateComment (
     comment_id: commentId
   };
 
-  if (core.getInput("body")) {
+  if (core.getInput("body") || ifUpdateBody) {
     if (updateMode === 'append') {
       params.body = `${comment_body}\n${body}`;
     } else {
@@ -6617,6 +6646,7 @@ module.exports = {
   doCreateIssue,
   doCreateIssueContent,
   doDeleteComment,
+  doMarkDuplicate,
   doLockIssue,
   doOpenIssue,
   doRemoveAssignees,
@@ -6646,6 +6676,7 @@ const {
   doCreateIssue,
   doCreateIssueContent,
   doDeleteComment,
+  doMarkDuplicate,
   doLockIssue,
   doOpenIssue,
   doRemoveAssignees,
@@ -6674,6 +6705,7 @@ const ALLACTIONS = [
   'create-issue',
   'delete-comment',
   'lock-issue',
+  'mark-duplicate',
   'open-issue',
   'remove-assignees',
   'remove-labels',
@@ -6715,7 +6747,9 @@ async function main() {
       updateMode = 'replace';
     }
 
+    // actions
     const actions = core.getInput("actions", { required: true });
+
     const actionsArr = actions.split(',');
     actionsArr.forEach(item => {
       testActions(item.trim());
@@ -6753,6 +6787,9 @@ async function main() {
         case 'lock-issue':
           await doLockIssue(owner, repo, issueNumber);
           break;
+        case 'mark-duplicate':
+          await doMarkDuplicate(owner, repo, labels);
+          break;
         case 'open-issue':
           await doOpenIssue(owner, repo, issueNumber);
           break;
diff --git a/docs/base.en-US.md b/docs/base.en-US.md
index 917c6cc..4a8b096 100644
--- a/docs/base.en-US.md
+++ b/docs/base.en-US.md
@@ -229,6 +229,37 @@ jobs:
 | token | [Token explain](/en-US/guide/ref#-token) | string | ✔ | v1 |
 | issue-number | The number of issue | number | ✔ | v1 |
 
+## `mark-duplicate`
+
+Quickly mark duplicate issue.
+
+```yml
+name: Issue Mark Duplicate
+
+on:
+  issue_comment:
+    types: [created, edited]
+
+jobs:
+  mark-duplicate:
+    runs-on: ubuntu-latest
+    steps:
+      - name: mark-duplicate
+        uses: actions-cool/issues-helper@v1.5
+        with:
+          actions: 'mark-duplicate'
+          token: ${{ secrets.GITHUB_TOKEN }}
+```
+
+| Param | Desc  | Type | Required | Version |
+| -- | -- | -- | -- | -- |
+| actions | Action type | string | ✔ | v1.5 |
+| token | [Token explain](/en-US/guide/ref#-token) | string | ✔ | v1.5 |
+| duplicate-command | Operation command, default is `/d` | string | ✖ | v1.5 |
+| duplicate-labels | Add additional labels to this issue | string | ✖ | v1.5 |
+| labels | Replace the labels of the issue | string | ✖ | v1.5 |
+| contents | Add [reaction](/en-US/guide/ref#-reactions-type) for this comment | string | ✖ | v1.5 |
+
 ## `open-issue`
 
 Open the specified issue.
diff --git a/docs/base.md b/docs/base.md
index b79f3fc..af49fe4 100644
--- a/docs/base.md
+++ b/docs/base.md
@@ -229,6 +229,37 @@ jobs:
 | token | [token 说明](/guide/ref#-token-说明) | string | ✔ | v1 |
 | issue-number | 指定的 issue | number | ✔ | v1 |
 
+## `mark-duplicate`
+
+快捷标记重复问题。
+
+```yml
+name: Issue Mark Duplicate
+
+on:
+  issue_comment:
+    types: [created, edited]
+
+jobs:
+  mark-duplicate:
+    runs-on: ubuntu-latest
+    steps:
+      - name: mark-duplicate
+        uses: actions-cool/issues-helper@v1.5
+        with:
+          actions: 'mark-duplicate'
+          token: ${{ secrets.GITHUB_TOKEN }}
+```
+
+| 参数 | 描述 | 类型 | 必填 | 版本 |
+| -- | -- | -- | -- | -- |
+| actions | 操作类型 | string | ✔ | v1.5 |
+| token | [token 说明](/guide/ref#-token-说明) | string | ✔ | v1.5 |
+| duplicate-command | 操作命令，默认为 `/d` | string | ✖ | v1.5 |
+| duplicate-labels | 为该 issue 额外增加 labels | string | ✖ | v1.5 |
+| labels | 替换该 issue 的 labels | string | ✖ | v1.5 |
+| contents | 为该评论的增加 [reaction](/guide/ref#-reactions-类型) | string | ✖ | v1.5 |
+
 ## `open-issue`
 
 打开指定 issue。
diff --git a/docs/changelog.en-US.md b/docs/changelog.en-US.md
index bb046b2..a8c24a1 100644
--- a/docs/changelog.en-US.md
+++ b/docs/changelog.en-US.md
@@ -21,4 +21,4 @@ toc: menu
   uses: actions-cool/issues-helper@main
 ```
 
-<embed src="./log.md"></embed>
+<embed src="../changelog.md"></embed>
diff --git a/docs/changelog.md b/docs/changelog.md
index 2af26a4..9df4545 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -21,4 +21,4 @@ toc: menu
   uses: actions-cool/issues-helper@main
 ```
 
-<embed src="./log.md"></embed>
+<embed src="../changelog.md"></embed>
diff --git a/package.json b/package.json
index 146325d..ceb0d4f 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "issue-helper",
-  "version": "1.4.0",
+  "version": "1.5.0",
   "private": true,
   "description": "Some operations on issue.",
   "main": "src/main.js",
diff --git a/src/base.js b/src/base.js
index 1df0276..094bada 100644
--- a/src/base.js
+++ b/src/base.js
@@ -24,6 +24,8 @@ const octokit = new Octokit({ auth: `token ${token}` });
 const contents = core.getInput("contents");
 const issueContents = core.getInput("issue-contents");
 
+const context = github.context;
+
 async function doAddAssignees (owner, repo, issueNumber, assignees) {
   await octokit.issues.addAssignees({
     owner,
@@ -138,6 +140,32 @@ async function doLockIssue (owner, repo, issueNumber) {
   core.info(`Actions: [lock-issue][${issueNumber}] success!`);
 };
 
+async function doMarkDuplicate (owner, repo, labels) {
+  if (context.eventName != 'issue_comment') {
+    core.info(`This actions only support on 'issue_comment'!`);
+    return false;
+  }
+  const duplicateCommand = core.getInput("duplicate-command") || '/d';
+  const duplicateLabels = core.getInput("duplicate-labels");
+  
+  const commentId = context.payload.comment.id;
+  const commentBody = context.payload.comment.body;
+  const issueNumber = context.payload.issue.number;
+
+  if (commentBody.startsWith(duplicateCommand) && commentBody.split(' ')[0] == duplicateCommand) {
+    const nextBody = commentBody.replace(duplicateCommand, 'Duplicate of');
+    await doUpdateComment(owner, repo, commentId, nextBody, 'replace', true);
+    if (duplicateLabels) {
+      await doAddLabels(owner, repo, issueNumber, duplicateLabels);
+    }
+    if (labels) {
+      await doSetLabels(owner, repo, issueNumber, labels);
+    }
+  } else {
+    core.info(`This comment body should start whith 'duplicate-command'`);
+  }
+};
+
 async function doOpenIssue (owner, repo, issueNumber) {
   await octokit.issues.update({
     owner,
@@ -204,7 +232,8 @@ async function doUpdateComment (
   repo,
   commentId,
   body,
-  updateMode
+  updateMode,
+  ifUpdateBody,
 ) {
   const comment = await octokit.issues.getComment({
     owner,
@@ -219,7 +248,7 @@ async function doUpdateComment (
     comment_id: commentId
   };
 
-  if (core.getInput("body")) {
+  if (core.getInput("body") || ifUpdateBody) {
     if (updateMode === 'append') {
       params.body = `${comment_body}\n${body}`;
     } else {
@@ -355,6 +384,7 @@ module.exports = {
   doCreateIssue,
   doCreateIssueContent,
   doDeleteComment,
+  doMarkDuplicate,
   doLockIssue,
   doOpenIssue,
   doRemoveAssignees,
diff --git a/src/main.js b/src/main.js
index 9d8ed18..969c64b 100644
--- a/src/main.js
+++ b/src/main.js
@@ -10,6 +10,7 @@ const {
   doCreateIssue,
   doCreateIssueContent,
   doDeleteComment,
+  doMarkDuplicate,
   doLockIssue,
   doOpenIssue,
   doRemoveAssignees,
@@ -38,6 +39,7 @@ const ALLACTIONS = [
   'create-issue',
   'delete-comment',
   'lock-issue',
+  'mark-duplicate',
   'open-issue',
   'remove-assignees',
   'remove-labels',
@@ -79,7 +81,9 @@ async function main() {
       updateMode = 'replace';
     }
 
+    // actions
     const actions = core.getInput("actions", { required: true });
+
     const actionsArr = actions.split(',');
     actionsArr.forEach(item => {
       testActions(item.trim());
@@ -117,6 +121,9 @@ async function main() {
         case 'lock-issue':
           await doLockIssue(owner, repo, issueNumber);
           break;
+        case 'mark-duplicate':
+          await doMarkDuplicate(owner, repo, labels);
+          break;
         case 'open-issue':
           await doOpenIssue(owner, repo, issueNumber);
           break;