The security of mobile networks has become a focus in recent years. However，the analysis on the security situation as well as the defense capabilities system construction in mobile networks is still a newborn research area in China. This article analyzes the mobile security situation of China in 2016，and illustrates the latest progress and problems of the defense capabilities building from the perspective of legal norms，administrative supervision and technical support. Finally，this article gives some suggestions on defense capabilities building，including strengthening the overall planning，improving the legal standards and integration of all resources.