diff --git a/ios/CDrop/MacApp/MacNotifier.swift b/ios/CDrop/MacApp/MacNotifier.swift
new file mode 100644
index 0000000..cc02489
--- /dev/null
+++ b/ios/CDrop/MacApp/MacNotifier.swift
@@ -0,0 +1,22 @@
+#if os(macOS)
+import AppKit
+import UserNotifications
+
+// 窗口非前台时的原生系统通知（收到消息 / 文件）。对齐桌面 app.ShowNotification：前台事件由应用内
+// NoticeOverlay / 未读红点负责，仅当 app 非活跃（NSApp.isActive == false）才发系统通知，避免与应用内
+// 提示重复。通知授权已由引擎启动时的 PushRegistry.requestAuthorizationAndRegister 一并请求。
+enum MacNotifier
+{
+    // 仅在 app 非活跃时发。title/body 由调用点给出（已是用户可读文本）。
+    static func notifyIfInactive(title: String, body: String)
+    {
+        guard !NSApp.isActive else { return }
+        let content = UNMutableNotificationContent()
+        content.title = title
+        content.body = body
+        content.sound = .default
+        let req = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: nil)
+        UNUserNotificationCenter.current().add(req)
+    }
+}
+#endif
diff --git a/ios/CDrop/MacApp/MacRootView.swift b/ios/CDrop/MacApp/MacRootView.swift
index cdd77c0..c2e923c 100644
--- a/ios/CDrop/MacApp/MacRootView.swift
+++ b/ios/CDrop/MacApp/MacRootView.swift
@@ -1,4 +1,5 @@
 #if os(macOS)
+import AppKit
 import SwiftUI
 
 // 桌面根界面：NavigationSplitView 侧栏（传输 / 文件 / 消息 / 设备 / 设置）+ 详情 NavigationStack，
@@ -210,6 +211,7 @@ struct MacSettingsView: View
     @Environment(EngineController.self) private var engine
     @Environment(AuthManager.self) private var auth
     @AppStorage("macClipboardAutoSync") private var autoSync = true
+    @AppStorage("macDownloadDir") private var downloadDirPath = ""
     @State private var nameDraft = DeviceNameStore.value
 
     private var signalingLabel: String
@@ -245,6 +247,11 @@ struct MacSettingsView: View
                 Button("上传本机剪贴板") { engine.uploadClipboard() }
                 Button("拉取云剪贴板到本机") { engine.pullClipboard() }
             }
+            Section("接收")
+            {
+                LabeledContent("保存到", value: downloadDirDisplay)
+                Button("选择目录…") { pickDownloadDir() }
+            }
             Section("引擎")
             {
                 LabeledContent("状态", value: engine.status)
@@ -280,5 +287,23 @@ struct MacSettingsView: View
         guard !name.isEmpty else { return }
         engine.renameSelf(to: name)
     }
+
+    private var downloadDirDisplay: String
+    {
+        downloadDirPath.isEmpty ? "下载（默认）" : (downloadDirPath as NSString).abbreviatingWithTildeInPath
+    }
+
+    private func pickDownloadDir()
+    {
+        let panel = NSOpenPanel()
+        panel.canChooseFiles = false
+        panel.canChooseDirectories = true
+        panel.allowsMultipleSelection = false
+        panel.prompt = "选择"
+        if panel.runModal() == .OK, let url = panel.url
+        {
+            downloadDirPath = url.path
+        }
+    }
 }
 #endif
diff --git a/ios/CDrop/Sources/Engine/DownloadManager.swift b/ios/CDrop/Sources/Engine/DownloadManager.swift
index b792784..c5a2cd5 100644
--- a/ios/CDrop/Sources/Engine/DownloadManager.swift
+++ b/ios/CDrop/Sources/Engine/DownloadManager.swift
@@ -16,7 +16,20 @@ final class DownloadManager
 
     private func downloadDir() -> URL
     {
+        #if os(macOS)
+        // macOS：可配置接收目录（UserDefaults macDownloadDir，设置页选）。未配 / 已失效则回退到系统
+        // 「下载」目录（比「文稿」更符桌面直觉）。非沙盒构建用普通路径即可；沙盒分发（Phase 6）须改
+        // 安全作用域书签。
+        if let path = UserDefaults.standard.string(forKey: "macDownloadDir"), !path.isEmpty
+        {
+            let url = URL(fileURLWithPath: path, isDirectory: true)
+            if FileManager.default.fileExists(atPath: url.path) { return url }
+        }
+        return FileManager.default.urls(for: .downloadsDirectory, in: .userDomainMask).first
+            ?? FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
+        #else
         return FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
+        #endif
     }
 
     // 列出已落盘的接收文件（Documents 顶层，排除流式临时 .part / 隐藏文件），最近的在前。
diff --git a/ios/CDrop/Sources/Engine/EngineController.swift b/ios/CDrop/Sources/Engine/EngineController.swift
index 0cf4a74..51e1c74 100644
--- a/ios/CDrop/Sources/Engine/EngineController.swift
+++ b/ios/CDrop/Sources/Engine/EngineController.swift
@@ -969,6 +969,10 @@ extension EngineController: WKScriptMessageHandler
                 if isNew, item.direction == "incoming", item.peerName != activeConversation
                 {
                     unreadByPeer[item.peerName, default: 0] += 1
+                    #if os(macOS)
+                    // 窗口非前台时发系统通知（对齐桌面）；前台由应用内未读红点负责。
+                    MacNotifier.notifyIfInactive(title: item.peerName, body: item.text)
+                    #endif
                 }
             }
         case "transferDone":
@@ -976,6 +980,13 @@ extension EngineController: WKScriptMessageHandler
             if let p = payload as? [String: Any], let item = Self.parseTransfer(p)
             {
                 noteIncomingTransfer(item)   // 极快传输可能跳过活跃阶段，这里补计未读（#5，已 seen 则不重复）
+                #if os(macOS)
+                // 窗口非前台时，收到文件发系统通知（对齐桌面）。
+                if item.direction == "incoming", item.state == "completed"
+                {
+                    MacNotifier.notifyIfInactive(title: "收到文件", body: item.fileName)
+                }
+                #endif
                 transfers.removeAll { $0.sessionId == item.sessionId }
                 history.removeAll { $0.sessionId == item.sessionId }
                 history.insert(item, at: 0)