Abstract: To evaluate the ride comfort of vehicle, the 8-degree-of-freedom dynamic model of the double-motor-driven electric vehicle with front and rear axles was established based on MATLAB/Simulink software with considering the vertical degrees of freedom of four wheels, the vertical movement of driver and seat and the vertical movement of body, the pitching movement, the roll movement. With the excitation input of white noise of grade C pavement, the acceleration speeds of center of mass, roll, pitch and seat of the body were simulated and analyzed respectively. Particle swarm optimization（PSO） was used to optimize the system parameters, and the optimized front and rear suspension stiffness and damping coefficient were obtained. The simulation validation of the optimized model shows that the ride comfort of the electric vehicle driven by front and rear axle dual motors is improved, and the root mean square value of the weighted acceleration at the optimized seat is significantly reduced. The theoretical optimum value is only 43.8% of that before the optimization, which is within the comfort limit. The mean square root values of the weighted acceleration at the foot and back are also reduced to some extent, and the theoretical optimum values are 42.1% and 44.0% of those before optimization, respectively.