This paper states the principles of pipeline leak detection, the module structure and characteristics of USB AE, meanwhile, analyzes the limitations of the existing USB acoustic emission detection system. Based on the above, with Visual Studio 2012 as application development platform, windows 32 application project is designed and researched a portable USB acoustic emission detection system for pipeline leak. Furthermore, by pipeline leakage simulation experiments, we verify the system design is feasible, achieve the acoustic emission signal acquisition and data processing, and conducts noise analysis combined with the experimental data.