Abstract: In order to improve the reliability of unmanned-vehicle control system, a fault-tolerant control method was proposed for unmanned vehicle path following, considering the influence of both steering control system fault and unknown disturbance on path-tracking effect of unmanned vehicle. Firstly, analyzing the input fault of steering control system and characterizing nominal fault from the unknown system interference, a mathematical model was established. And then, a differential equation of nominal fault was constructed with a high-order sliding mode observer, and the estimation method of vehicle sideslip angle and nominal fault was designed based on adaptive cubature Kalman filter, providing reliable information source for fault-tolerant control of unmanned vehicle. Finally, a fault-tolerant controller was designed based on sliding mode control method for path following of unmanned vehicle to prove its convergence. The results of co-simulation and hardware in the loop test show that, the proposed estimation method can get accurate and reliable estimation results of vehicle sideslip angle and nominal fault, and compared with no fault-tolerant control, the designed fault-tolerant path following controller can significantly improve the control performance of vehicle in the face of fault and interference, and at the same time ensure the path following ability and its own stability of vehicle.