Web services bring more conveniences for users and developers. However, it makes user face the problem of service information explosion. The personalized service recommendation solves the problem. This paper proposes a method to predicting the system reliability which bases on user context information in mobile computing environment. The method construct user behavior model by formatting user location context and then quantitative verification is performed to estimating whether the recommended service meet the requirements of users. Finally, experiments are carried out to demonstrate the effectiveness of our method.