In order to improve the shift quality of electric vehicles equipped with combined clutch planetary transmission with two gears, a dynamic model of shift process was established.Longitudinal jerk and friction work were chosen as the comprehensive control targets by considering the changes of the motor torque and the load torque.The linear quadratic optimal control model of combined clutch friction torque was built to realize the optimal control trajectory of clutch oil pressure.Compared with the optimal control under different throttle openings and road slopes, the simulation results have shown that the optimal trajectory can effectively improve the shift quality and it is more sensitive to the changes of the motor torque than that of the load torque.