diff --git a/src/app/api/offline-download/route.ts b/src/app/api/offline-download/route.ts
index 6609951..3e670a5 100644
--- a/src/app/api/offline-download/route.ts
+++ b/src/app/api/offline-download/route.ts
@@ -304,6 +304,21 @@ export async function DELETE(request: NextRequest) {
 
     const downloader = getDownloader();
 
+    // 如果任务正在下载，先标记为取消状态，等待下载停止
+    const downloadPromise = activeDownloads.get(taskId);
+    if (downloadPromise) {
+      // 将任务状态设置为 error，这样下载器会停止下载
+      task.status = 'error';
+      task.errorMessage = '任务已被删除';
+      tasks.set(taskId, task);
+
+      // 从活跃下载列表中移除
+      activeDownloads.delete(taskId);
+
+      // 等待一小段时间，让下载操作有机会停止
+      await new Promise(resolve => setTimeout(resolve, 500));
+    }
+
     // 删除文件
     await downloader.deleteTask(task);
 
@@ -311,12 +326,6 @@ export async function DELETE(request: NextRequest) {
     tasks.delete(taskId);
     saveTasks(); // 持久化任务
 
-    // 如果正在下载，等待下载完成后再删除
-    const downloadPromise = activeDownloads.get(taskId);
-    if (downloadPromise) {
-      activeDownloads.delete(taskId);
-    }
-
     return NextResponse.json({ message: '任务已删除' });
   } catch (error) {
     console.error('删除任务失败:', error);
diff --git a/src/contexts/DownloadContext.tsx b/src/contexts/DownloadContext.tsx
index 50c4c33..73e84eb 100644
--- a/src/contexts/DownloadContext.tsx
+++ b/src/contexts/DownloadContext.tsx
@@ -21,7 +21,7 @@ interface DownloadContextType {
   ) => Promise<void>;
   startTask: (taskId: string) => void;
   pauseTask: (taskId: string) => void;
-  cancelTask: (taskId: string) => void;
+  cancelTask: (taskId: string) => Promise<void>;
   retryFailedSegments: (taskId: string) => void;
   getProgress: (taskId: string) => number;
   downloadingCount: number;
@@ -509,8 +509,8 @@ export function DownloadProvider({ children }: { children: React.ReactNode }) {
     startNextPendingTask(downloader);
   }, [downloader, startNextPendingTask]);
 
-  const cancelTask = useCallback((taskId: string) => {
-    downloader.cancelTask(taskId);
+  const cancelTask = useCallback(async (taskId: string) => {
+    await downloader.cancelTask(taskId);
     setTasks(downloader.getAllTasks());
     // 保存任务状态到 IndexedDB（删除被取消的任务）
     saveTasks(downloader.getAllTasks());
diff --git a/src/lib/m3u8-downloader.ts b/src/lib/m3u8-downloader.ts
index fc1de0a..f965f43 100644
--- a/src/lib/m3u8-downloader.ts
+++ b/src/lib/m3u8-downloader.ts
@@ -241,11 +241,17 @@ export class M3U8Downloader {
   /**
    * 取消任务
    */
-  cancelTask(taskId: string): void {
+  async cancelTask(taskId: string): Promise<void> {
     const task = this.tasks.get(taskId);
     if (!task) return;
 
     this.abortRequests(task);
+
+    // 如果是 filesystem 模式且任务未完成，删除已下载的文件
+    if (task.downloadMode === 'filesystem' && task.status !== 'done' && task.filesystemDirHandle) {
+      await this.deleteFilesystemTask(task);
+    }
+
     this.tasks.delete(taskId);
 
     if (this.currentTask?.id === taskId) {
@@ -253,6 +259,30 @@ export class M3U8Downloader {
     }
   }
 
+  /**
+   * 删除 filesystem 模式下的任务文件
+   */
+  private async deleteFilesystemTask(task: M3U8DownloadTask): Promise<void> {
+    if (!task.filesystemDirHandle || !task.source || !task.videoId || task.episodeIndex === undefined) {
+      return;
+    }
+
+    try {
+      // 获取目标目录
+      const sourceDirHandle = await task.filesystemDirHandle.getDirectoryHandle(task.source, { create: false });
+      const videoIdDirHandle = await sourceDirHandle.getDirectoryHandle(task.videoId, { create: false });
+
+      // 删除 ep{n} 目录
+      const epDirName = `ep${task.episodeIndex + 1}`;
+      await videoIdDirHandle.removeEntry(epDirName, { recursive: true });
+
+      console.log(`已删除未完成的下载文件: ${task.source}/${task.videoId}/${epDirName}`);
+    } catch (error) {
+      // 如果目录不存在或删除失败，忽略错误
+      console.warn('删除文件失败（可能目录不存在）:', error);
+    }
+  }
+
   /**
    * 获取任务信息
    */