Researches on leak detection system of gas network are significant to fault pipelines diagnosis. In the daily operation of city gas pipeline network, pipeline leakage is the most risky failure type. This paper attempts to review and analyze the existing gas network leak detection systems, meanwhile, design a new kind of leak detection system for daily monitoring and leakage detection of gas network. The greatest advantage of this system is to be able to do all kinds of leak experimental research, especially has great reference value for the leak detection task in colleges and universities.