Abstract: Investigates the matching calculation of electromechanical transmission system for electric cars.The matching calculation of electromechanical transmission system for electric cars including AC induction motor,reducer,motor controller,and power battery,is put forward according to the power performance index of the vehicle,especially for the motor and reducer.Simulation of electric car electromechanical transmission system based on Matlab/Simulink is performed.Results of simulation of the basic cycle condition about electric vehicle verify that the electromechanical transmission system has good dynamic torque and speed characteristics,and the results of simulation of the system power performance satisfy the demand of design.The matching calculation method of the electromechanical transmission system for electric car proved itself to be effective and feasible.