In view of the fuel cell with lower level and wider changing range output voltage characteristic, the paper studied a kind of power converter suitable for fuel cell power generation system. Firstly, established the fuel cell power supply system with multi stage ,including the former stage new high-gain dc converter and later stage-AC converter, Then respectively analysised its working principle and designed the corresponding control strategy. The former stage-new high gain DC converter adopted average current control strategy, which made the fuel cell output voltage with higher gain and stability, meanwhile with lower switch tube voltage/current stress; later stage-AC converter introduced the improved virtual synchronous generator algorithm, which can track the load changing fastly and accurately , adjust the frequency without error and have good reactive voltage sag characteristics. Finally constructed the system model and simulated in the MATLAB/simulink, then constructed the experimental platform for the front-end DC converter, the simulation and experiment results verify the validity of the theoretical analysis.