The disadvantage that ordinary active suspension model is in low accuracy and practicability which is caused by the neglect of actuator motion is brought forth through analyzing the assemble of active suspension. The model including hydraulic system parameters is obtained through building the active suspension hydraulic system model. The weighting coefficient matrix of car body acceleration, suspension deflection, and tyre displacement is determined through analyzing the principle of LQG control and the active suspension LQG control strategy is brought out. The conclusion that active suspension promote more control stability and riding comfort than passive suspension and PID control is made by simulation and comparing with passive suspension and active suspension PID control. The force output amplitude performance of the LQG control is better than the PID control which can be get from the force signals.