diff --git a/dist/index.js b/dist/index.js
index cb91306..0b0ca35 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -14934,7 +14934,7 @@ function doMarkDuplicate(comment, closeReason, labels, emoji) {
             if (duplicateLabels) {
                 newLabels = [...newLabels, ...(0, actions_util_1.dealStringToArr)(duplicateLabels)];
             }
-            if (labels) {
+            if (labels === null || labels === void 0 ? void 0 : labels.length) {
                 newLabels = [...labels];
             }
             if (newLabels.length > 0) {
diff --git a/src/helper/advanced.ts b/src/helper/advanced.ts
index 24e9f0a..08055f1 100644
--- a/src/helper/advanced.ts
+++ b/src/helper/advanced.ts
@@ -344,7 +344,7 @@ export async function doMarkDuplicate(
     if (duplicateLabels) {
       newLabels = [...newLabels, ...dealStringToArr(duplicateLabels)];
     }
-    if (labels) {
+    if (labels?.length) {
       newLabels = [...labels];
     }
     if (newLabels.length > 0) {