Abstract: This paper describes the principle of a front-wheel drive hydraulic hybrid vehicle,which can improve the power performance and cut down the fuel consumption and exhaust emissions.Simulation analysis employing the SimulationX software was carried out based on a specified passenger car during the course of braking.In terms of the definition of the severity of energy recovering,the braking performance was theoretically analyzed.Results indicate that the vehicle regenerative braking process is smooth and braking energy is quickly recovered by the hydraulic pump/motor and hydraulic accumulators.The hydraulic hybrid vehicle has a much higher synchronized adhesion coefficient than the ordinary vehicle,which can enhance the directional stability in the braking process.Meanwhile,it is more satisfying to hydraulically brake the vehicle on rough roads and it is not suitable for hydraulically recovering the braking energy on the extreme road whose adhesion coefficient is less than the synchronized adhesion coefficient.