The primary power supply based on lithium battery combines lithium battery and high-voltage charging technology, which is the key to realize the lightweight and high-frequency of electromagnetic launch weapon system. In this paper, five charging methods are deeply studied: constant voltage charging, direct current chopping, cascade boost, high-frequency chopping, series resonant boost. The electrical composition, working principle, technical characteristics and other aspects are analyzed and compared, and the simulation model is established by matlab. The analysis shows that the three charging methods of cascade boost, high frequency chopping and series resonant boost are the current mainstream technical routes, with high reliability and technical maturity, which are suitable for a variety of different operating conditions.