In the construction of new type power system, in order to reduce the demand pressure on the city's power distribution capacity and promote the application of pure electric buses, this paper proposed the methods to optimize the charging time, charging duration and charging power of pure electric bus in combination with the vehicle operation and charging load characteristics. The mathematical model of charging load optimization and economic operation of fast charging station is established, and the optimization model is solved by particle swarm optimization and hierarchical sequence method. Through the simulation analysis of the cases, the optimization effect of the charging power combined with charging time is the best, which can effectively reduce the distribution capacity of the fast charging station and reduce the charging electricity cost.