Aiming at the problem of multiple sensor fault detection and reconstruction in the electric forklift stability control system, a sliding mode observer with adaptive regulation law is proposed to realize sensor fault detection and reconstruction. Starting from the threedegreeoffreedom model of the forklift, a linear state equation with output disturbance is constructed as its equivalent forklift sensor fault model, and the sensor fault is converted into an actuator fault by defining an auxiliary state variable as an output signal filter. According to the fault model and sliding mode control theory, the sensor fault detection and reconstruction method based on sliding mode observer is given, based on the adaptive algorithm, the observer design has the advantage of not knowing the upper limit of unknown fault. Finally, the experimental results show that the method is effective.