Abstract: The modeling method of the three-port bidirectional DC/ DC converter is mainly for the circuit structure in which the resonant tank is a single inductor,and the topology modeling of the resonant tank for the LC resonance is in lack. This paper uses a generalized state space averaging method to model the series resonant three-port DC/ DC converter,and studies the system*s working mode,dynamic modeling process and control strategy. By building the simulation model in MATLAB/ Simulink,the power flow in different working modes is simulated and verified. The results show that the control strategy designed by the modeling method can achieve good system dynamic response characteristics.