LanScreen
下载Download

副屏，只需要一个浏览器 A second monitor.
Just open a browser.

在 Mac 上运行 LanScreen，用同一局域网的任意手机或平板打开浏览器，立刻获得一块真正的扩展副屏。副屏上不需要安装任何软件，也不用注册账号。 Run LanScreen on your Mac, then open a browser on any phone or tablet on the same network. You get a real extended display — with nothing to install on the second device, and no account.

下载 macOS 版Download for macOS 工作原理How it works
副屏零安装Zero install 副屏只需打开浏览器Nothing to install on the second screen
60 fps 硬件编码60 fps hardware VideoToolbox + WebCodecs 端到端硬编解VideoToolbox encode, WebCodecs decode
USB 有线模式Wired USB mode 安卓设备延迟极低，还顺带充电Near-zero latency on Android, and it charges
http://192.168.1.42:8080
MacBook 与平板、手机通过浏览器扩展桌面连接
三步上手Get started

从打开应用到用上副屏，不到一分钟From launch to a working second screen, in under a minute

不需要数据线，不需要在副屏上安装任何东西，也不需要注册。No cable required, nothing to install on the second device, no sign-up.

1

在 Mac 上运行Run it on your Mac

启动 LanScreen，菜单栏出现图标，应用会自动创建一个系统级虚拟显示器，并显示配对地址。Launch LanScreen. A menu-bar icon appears, the app creates a system-level virtual display, and shows a pairing address.

2

在副屏浏览器打开地址Open the address in a browser

在手机或平板浏览器输入面板上显示的局域网地址，无线连接即刻建立。Type the LAN address shown in the panel into the browser on your phone or tablet — the link is established instantly.

http://192.168.x.x:8080
3

把窗口拖过去Drag windows over

系统把它当作真实显示器：扩展桌面、全屏播放、多任务窗口，全部照常使用。macOS treats it as a real display: extend your desktop, go full-screen, run multi-window — everything works as usual.

安卓有线模式Wired USB mode

一根数据线，延迟极低One cable. Near-zero latency.

用数据线连接安卓设备，在 LanScreen 菜单里选择「使用数据线」，应用会自动完成端口转发。副屏浏览器打开 localhost 地址即可 —— 画面走线缆而不是 Wi-Fi，不受无线抖动影响，同时顺带给设备充电。适合游戏、实时预览、会议演示等对延迟敏感的场景。 Connect an Android device over USB and choose “Use a cable” from the LanScreen menu — the app sets up the port forwarding for you. Open the localhost address in the browser and frames travel over the cable instead of Wi-Fi: immune to wireless jitter, and your device charges while it works. Ideal for gaming, live preview, and presentations.

应用自动执行Handled automatically
adb reverse tcp:8080 tcp:8080
adb reverse tcp:8081 tcp:8081

需要设备已开启「开发者选项 → USB 调试」，且 Mac 上可找到 adb。Requires USB debugging enabled on the device and adb available on the Mac.

Wi-Fi 模式Wi-Fi mode 随处可用Anywhere

无需线缆，副屏设备放哪都行。只要与 Mac 处在同一局域网即可，建议使用稳定的 5 GHz Wi-Fi。No cable, and the device can sit anywhere. All it needs is a shared local network with your Mac — a stable 5 GHz Wi-Fi is recommended.

USB 有线模式USB wired mode 最低延迟Lowest latency

画面完全不走网络，延迟极低且稳定，不受路由器负载与信号干扰影响；设备在使用的过程中同时充电。Frames never touch the network: latency is minimal and consistent, unaffected by router load or signal interference — and the device charges while in use.

特性Features

一块真正的显示器，而不是投屏A real display, not a cast

它由 macOS 识别为系统显示器，因此扩展桌面、全屏、多任务的行为与普通外接屏完全一致。macOS recognises it as a system display, so extending, going full-screen and multitasking behave exactly like a physical monitor.

真·扩展显示器A true extended display

通过系统虚拟显示器接口创建，最高 2960×1848 HiDPI，是把桌面延伸出去，而不是把画面镜像一遍。Created through the system virtual-display interface up to 2960×1848 HiDPI. Your desktop is extended, not just mirrored.

硬件 H.264 端到端Hardware H.264 end to end

VideoToolbox 硬件编码，浏览器侧用 WebCodecs 硬解并由 WebGL 上屏，稳定 60 fps、低占用。Encoded in hardware by VideoToolbox, decoded in the browser with WebCodecs and rendered via WebGL — steady 60 fps at low cost.

任何设备都能用Works with any device

只要浏览器支持 WebCodecs：安卓平板、iPad、旧手机都行，Chrome、Edge、Samsung Internet 均可。Any browser with WebCodecs support: Android tablets, iPads, older phones — Chrome, Edge or Samsung Internet all work.

全屏运行与屏幕常亮Full-screen & always on

可添加到主屏幕作为 PWA 全屏运行，并保持屏幕常亮，副屏放一边就能一直当显示器用。Add it to the home screen as a PWA, run it full-screen, and keep the screen awake — leave it beside you and it stays a monitor.

自动重连Automatic reconnect

合盖唤醒、设备休眠、短暂断线后自动恢复推流，无需重新配对或刷新页面。After sleep, wake or a brief drop, streaming resumes on its own — no re-pairing, no refreshing the page.

本地直连，不留数据Local-only and private

画面只在你的局域网内点对点传输，不经过任何服务器，无第三方 SDK，也不收集任何数据。Frames travel peer-to-peer on your LAN only. No servers in between, no third-party SDKs, and no data collected.

工作原理How it works

全硬件流水线，浏览器负责最后一步An all-hardware pipeline — the browser does the last mile

Mac 负责创建显示器与编码，副屏浏览器只做解码和显示，因此副屏几乎不需要性能。The Mac creates the display and encodes; the second screen only decodes and paints — so it needs almost no horsepower.

虚拟显示器Virtual display 创建系统级显示器System-level display is created
屏幕采集Capture ScreenCaptureKit 抓帧ScreenCaptureKit grabs frames
硬件编码Hardware encode VideoToolbox 输出 H.264VideoToolbox produces H.264
本机传输Local transport HTTP + WebSocket 走局域网HTTP + WebSocket over your LAN
浏览器解码Browser decode WebCodecs 硬解 + WebGL 上屏WebCodecs decode + WebGL paint
系统要求Requirements

你需要准备的What you need

Mac
macOS 14 或更高macOS 14 or later

Apple Silicon 与 Intel 机型均支持，需要授予「屏幕录制」权限。Apple Silicon and Intel are both supported. Screen Recording permission is required.

副屏Second screen
支持 WebCodecs 的现代浏览器A modern browser with WebCodecs

Android 平板 / 手机、iPad、iPhone 均可，无需安装任何应用。Android tablets and phones, iPads and iPhones — nothing to install.

有线模式（可选）Wired mode (optional)
Android 设备 + adbAndroid device + adb

仅在需要最低延迟时使用；需要设备已开启 USB 调试。Only if you want the lowest latency; requires USB debugging enabled on the device.

下载 LanScreenDownload LanScreen

免费下载，无需注册。安装包体积小，不包含任何第三方追踪代码。Free to download, no account needed. A small installer with no third-party tracking.

Apple 芯片（M 系列）Apple silicon (M series) Intel 芯片Intel 查看发布页View releases

不确定选哪个？点屏幕左上角 → 「关于本机」，看「芯片」一栏：写着 Apple M… 就选 Apple 芯片；写着 Intel 就选 Intel。 Not sure which to pick? Go to → "About This Mac" and look at the Chip line: "Apple M…" means Apple silicon, "Intel" means Intel.

1拖进 ApplicationsDrag into Applications

打开 DMG，把 LanScreen 拖入应用程序文件夹。Open the DMG and drag LanScreen into your Applications folder.

2首次启动若被拦截If macOS blocks it

macOS 14 上右键点击图标选「打开」；macOS 15 及更高版本请到「系统设置 → 隐私与安全性」里点「仍要打开」。On macOS 14, right-click the icon and choose Open. On macOS 15 or later, allow it from System Settings → Privacy & Security → Open Anyway.

3授予权限Grant permission

在系统设置里允许「屏幕录制」，随后即可把副屏设备添加为扩展显示器。Allow Screen Recording in System Settings, then add your device as an extended display.

适用于 macOS 14+ · 当前版本 For macOS 14+ · Current version 1.0 · Apple 芯片与 Intel 分开提供安装包 · separate builds for Apple silicon and Intel

常见问题FAQ

你可能想问的Questions you might have

和 Sidecar、Duet 这类方案有什么区别？How is this different from Sidecar or Duet?
最大的区别是它不挑副屏设备：安卓平板、旧 iPad、甚至一部手机都能用；而且副屏上不需要安装任何 App，打开浏览器就能用。Sidecar 只能与 iPad 配对，Duet 需要在副屏上装客户端。The big difference is that it doesn’t care what the second device is: an Android tablet, an older iPad, even a phone will do — and there is nothing to install on it, just a browser. Sidecar only pairs with an iPad, and Duet needs a client app on the second screen.
iPhone 和 iPad 支持吗？Does it support iPhone and iPad?
支持。在 iOS / iPadOS 上打开 Safari 即可通过 Wi-Fi 使用。USB 有线低延迟模式目前仅支持 Android 设备。Yes. Open Safari on iOS or iPadOS and connect over Wi-Fi. The wired low-latency mode is currently Android-only.
为什么播放受版权保护的视频是黑屏？Why is DRM video black?
受版权保护的内容（如 Netflix、Apple TV+）由系统保护，屏幕采集只能拿到黑帧。普通网页、文档、代码编辑器、开发工具都不受影响。Copyright-protected playback — Netflix, Apple TV+ and similar — is guarded by the system, so screen capture only receives black frames. Regular web pages, documents, code editors and dev tools are unaffected.
需要联网或注册账号吗？Does it need internet or an account?
都不需要。应用完全离线运行，画面只在你的局域网内传输，没有登录环节，也不收集任何数据。Neither. The app runs fully offline, frames stay inside your local network, there is no sign-in, and no data is collected.
延迟和画质表现如何？How are latency and image quality?
局域网上通常只有几十毫秒，USB 有线模式下更低。分辨率可选 2960×1848 HiDPI 到 1480×924，默认 60 fps。Typically tens of milliseconds over LAN, and lower still in wired mode. Resolution ranges from 2960×1848 HiDPI down to 1480×924, at 60 fps by default.
安全吗？端口会暴露到公网吗？Is it safe? Are ports exposed to the internet?
不会。服务只在局域网内监听，不对外开放任何端口。同一网段的设备也需要知道你的配对地址才能连接。No. The service only listens on your local network and opens no ports to the internet. Even devices on the same subnet need to know your pairing address to connect.