An active fault-tolerant control strategy based on control law reconfiguration was put forward for vehicle semi-active suspension system. A 2-DOF quarter vehicle semi-active suspension system model and fault suspension model were built. Semi-active suspension fault detection and on line diagnosis of suspension actuator’s fault gain were realized by output residual error obtained from designing robust observer. Then, on the basis of LQG controller and on-line diagnosis, active fault-tolerant control was realized on fault suspension through adjusting LQG control law to design fault-tolerant controller based on control law reconfiguration. The results of simulation under Matlab/Simulink and bench experiment showed that active fault-tolerant control strategy based on control law reconfiguration could rapidly restore the comfort performance of fault suspension system to the level close to that of semi-active suspension in the absence of fault after 0.5 to 2.0 s delay, eliminate the effects caused by actuator fault, and increase the reliability of suspension control. 