diff --git a/src/routes/documents.js b/src/routes/documents.js
index 5e473a1..a8d4a08 100644
--- a/src/routes/documents.js
+++ b/src/routes/documents.js
@@ -78,7 +78,7 @@ router.get('/:id', async (req, res) => {
 // PUT /documents/:id - Update document
 router.put('/:id', async (req, res) => {
   try {
-    const { title, content, tags, type, priority, status } = req.body;
+    const { title, content, tags, type, priority, status, folderId } = req.body;
     const docService = getDocumentService();
     const doc = await docService.updateDocument(req.params.id, {
       title,
@@ -87,6 +87,7 @@ router.put('/:id', async (req, res) => {
       type,
       priority,
       status,
+      folderId,
     });
     res.json(doc);
   } catch (err) {
diff --git a/src/services/documentService.js b/src/services/documentService.js
index ba00377..c841307 100644
--- a/src/services/documentService.js
+++ b/src/services/documentService.js
@@ -469,7 +469,7 @@ export class DocumentService {
     };
   }
 
-  async updateDocument(docId, { title, content, tags, type, priority, status }) {
+  async updateDocument(docId, { title, content, tags, type, priority, status, folderId }) {
     const found = this._findDocById(docId);
     if (!found) {
       throw new NotFoundError('Document');
@@ -484,6 +484,7 @@ export class DocumentService {
     if (priority !== undefined) meta.priority = priority;
     if (status !== undefined) meta.status = status;
     if (tags !== undefined) meta.tags = tags.filter(t => t);
+    if (folderId !== undefined) meta.folderId = folderId;
     meta.updatedAt = now;
 
     // Rewrite markdown file