A mobile video monitoring system based on Node.js is designed by using OpenCV coupling with Web front-end technology in this paper. The system adopts B/S structure. Node.js server is built on windows system for acquisition and transmission of video data and OpenCV built on the same system is used for image processing and encoding. The client is made with Web front-end technology and Hybrid App development model running on the mobile terminal, to provide monitoring function. The test results show that under WiFi environment, the system carries out multi-user and real-time monitoring effectively.