Abstract: Several methods were applied to test the application program(APP)of railway 12306 system mobile phone in order to improve the overall software quality. Functional testing, performance testing, compatibility testing, security testing and other methods were used to find out the defects of the system before it goes online; A/B testing, gray level testing and other methods were used to timely understand the user feedback after the system goes online. The system capability, running stability and user experience of APP of 12306 mobile phone have been significantly improved by testing. Practice has proved that reasonable and effective design of test cases and different test methods can significantly improve the efficiency and quality of testing, which is an essential part of the system development process.