In order to reduce the probability of traffic accidents in China’s railway crossing, an intelligent alarming system based on combination of streaming media with motion detecting is presented. In the system, we use the Client/Server mode. The server is responsible for video capture, image processing, H.264 encoding and transmission of video and alarm information. The client which based on embedded wince device is responsible for receiving real-time video and alarm information. The design and implementation of all parts are expounded in this paper. The key technologies and algorithms are explained in detail. Experiments show the system can accurately detect obstacles, paly the video smooth and greatly reduce the risk of crossing traffic accidents.