With constant increase of the complicity of mobile applications,efficient testing techniques and tools gradually become essential to assure high-quality mobile applications. Based on capture-replay technique,in this paper we address an automatic testing solution for mobile applications on Google Android platform,and implement a black-box testing tool. Through presenting an example to depict the recording testing case and the process of script generation and replay,we dissect the design and implementation of key technique in capture-replay module of GUI automatic testing tool. The GUI testing tool is mainly used for regression test and can improve testing efficiency.