Abstract: In order to study the hybrid drive dynamic performance of engine and battery packs in the electric drive vehicle,uniform dynamic circuit of permanent magnet generator,rectifier and traction battery packs in the d-q coordinate of the generator rotor is built up in impedance equivalence,state(equation) and direct current water impedance is introduced to finish simulation and experiment of the dynamic model.Simulating the vehicle steering drive,the simulation results proved that the battery packs decrease the engine speed and torque wave,smooth the bus voltage in its acute change and have the ability to balance load and absorb the electric braking energy.