diff --git a/lightrag/api/routers/document_routes.py b/lightrag/api/routers/document_routes.py
index d6434e08..4b519628 100644
--- a/lightrag/api/routers/document_routes.py
+++ b/lightrag/api/routers/document_routes.py
@@ -542,6 +542,7 @@ def create_document_routes(
 
         Returns:
             InsertResponse: A response object containing the upload status and a message.
+                status can be "success", "duplicated", or error is thrown.
 
         Raises:
             HTTPException: If the file type is not supported (400) or other errors occur (500).
@@ -554,6 +555,13 @@ def create_document_routes(
                 )
 
             file_path = doc_manager.input_dir / file.filename
+            # Check if file already exists
+            if file_path.exists():
+                return InsertResponse(
+                    status="duplicated",
+                    message=f"File '{file.filename}' already exists in the input directory."
+                )
+
             with open(file_path, "wb") as buffer:
                 shutil.copyfileobj(file.file, buffer)
 
diff --git a/lightrag_webui/src/api/lightrag.ts b/lightrag_webui/src/api/lightrag.ts
index 8b59ccbf..364ecb44 100644
--- a/lightrag_webui/src/api/lightrag.ts
+++ b/lightrag_webui/src/api/lightrag.ts
@@ -109,7 +109,7 @@ export type QueryResponse = {
 }
 
 export type DocActionResponse = {
-  status: 'success' | 'partial_success' | 'failure'
+  status: 'success' | 'partial_success' | 'failure' | 'duplicated'
   message: string
 }
 
diff --git a/lightrag_webui/src/components/documents/UploadDocumentsDialog.tsx b/lightrag_webui/src/components/documents/UploadDocumentsDialog.tsx
index bf1d00b7..5c9a99bd 100644
--- a/lightrag_webui/src/components/documents/UploadDocumentsDialog.tsx
+++ b/lightrag_webui/src/components/documents/UploadDocumentsDialog.tsx
@@ -89,7 +89,13 @@ export default function UploadDocumentsDialog() {
                 }))
               })
 
-              if (result.status !== 'success') {
+              if (result.status === 'duplicated') {
+                uploadErrors[file.name] = t('documentPanel.uploadDocuments.fileUploader.duplicateFile')
+                setFileErrors(prev => ({
+                  ...prev,
+                  [file.name]: t('documentPanel.uploadDocuments.fileUploader.duplicateFile')
+                }))
+              } else if (result.status !== 'success') {
                 uploadErrors[file.name] = result.message
                 setFileErrors(prev => ({
                   ...prev,
diff --git a/lightrag_webui/src/locales/ar.json b/lightrag_webui/src/locales/ar.json
index 1775b1c5..f4e8f316 100644
--- a/lightrag_webui/src/locales/ar.json
+++ b/lightrag_webui/src/locales/ar.json
@@ -70,7 +70,8 @@
         "dropHere": "أفلت الملفات هنا",
         "dragAndDrop": "اسحب وأفلت الملفات هنا، أو انقر للاختيار",
         "removeFile": "إزالة الملف",
-        "uploadDescription": "يمكنك رفع {{isMultiple ? 'عدة' : count}} ملفات (حتى {{maxSize}} لكل منها)"
+        "uploadDescription": "يمكنك رفع {{isMultiple ? 'عدة' : count}} ملفات (حتى {{maxSize}} لكل منها)",
+        "duplicateFile": "اسم الملف موجود بالفعل في ذاكرة التخزين المؤقت للخادم"
       }
     },
     "documentManager": {
diff --git a/lightrag_webui/src/locales/en.json b/lightrag_webui/src/locales/en.json
index 7d89f040..a48eded3 100644
--- a/lightrag_webui/src/locales/en.json
+++ b/lightrag_webui/src/locales/en.json
@@ -70,7 +70,8 @@
         "dropHere": "Drop the files here",
         "dragAndDrop": "Drag and drop files here, or click to select files",
         "removeFile": "Remove file",
-        "uploadDescription": "You can upload {{isMultiple ? 'multiple' : count}} files (up to {{maxSize}} each)"
+        "uploadDescription": "You can upload {{isMultiple ? 'multiple' : count}} files (up to {{maxSize}} each)",
+        "duplicateFile": "File name already exists in server cache"
       }
     },
     "documentManager": {
diff --git a/lightrag_webui/src/locales/fr.json b/lightrag_webui/src/locales/fr.json
index 0c56f524..600503ee 100644
--- a/lightrag_webui/src/locales/fr.json
+++ b/lightrag_webui/src/locales/fr.json
@@ -70,7 +70,8 @@
         "dropHere": "Déposez les fichiers ici",
         "dragAndDrop": "Glissez et déposez les fichiers ici, ou cliquez pour sélectionner",
         "removeFile": "Supprimer le fichier",
-        "uploadDescription": "Vous pouvez télécharger {{isMultiple ? 'plusieurs' : count}} fichiers (jusqu'à {{maxSize}} chacun)"
+        "uploadDescription": "Vous pouvez télécharger {{isMultiple ? 'plusieurs' : count}} fichiers (jusqu'à {{maxSize}} chacun)",
+        "duplicateFile": "Le nom du fichier existe déjà dans le cache du serveur"
       }
     },
     "documentManager": {
diff --git a/lightrag_webui/src/locales/zh.json b/lightrag_webui/src/locales/zh.json
index 23389f47..6f182f38 100644
--- a/lightrag_webui/src/locales/zh.json
+++ b/lightrag_webui/src/locales/zh.json
@@ -70,7 +70,8 @@
         "dropHere": "将文件拖放到此处",
         "dragAndDrop": "拖放文件到此处，或点击选择文件",
         "removeFile": "移除文件",
-        "uploadDescription": "您可以上传{{isMultiple ? '多个' : count}}个文件（每个文件最大{{maxSize}}）"
+        "uploadDescription": "您可以上传{{isMultiple ? '多个' : count}}个文件（每个文件最大{{maxSize}}）",
+        "duplicateFile": "文件名与服务器上的缓存重复"
       }
     },
     "documentManager": {