In order to solve the system instability caused by the failure of electro-magnetic hybrid active suspension， a multi-mode switching fault-tolerant control strategy is designed. The 1/4 vehicle model including two degree of freedom suspension， linear motor mathematical model and solenoid valve damper polynomial model are established respectively. The fault-tolerant control strategy is proposed， in which the suspension state is estimated by unknown input observer， the suspension system's sprung mass acceleration is taken as the normal state switching condition， and the sprung mass acceleration residual and stability module are taken as the fault state switching condition. The suspension performance under different gain faults is simulated and analyzed， and the bench test is carried out. Results show that： under the multi-mode switching fault-tolerant control， the root mean square value of sprung mass acceleration is reduced by 31.35% compared with the fault state. The multi-mode switching fault-tolerant control strategy can realize the mode switching of suspension in normal state and fault state， and the dynamic performance of suspension is improved.