To solve the problem of chattering and phase delay in traditional sliding mode observer(SMO), an adaptive fuzzy sliding mode observer for sensorless control of permanent magnet synchronous motor(PMSM) is proposed.According to the Lyapunov stability theorem, an adaptive fuzzy sliding mode observer is constructed to guarantee the stability of the system.A fuzzy control system is designed by analyzing the influence of sliding mode gain on the chattering of the system.The fuzzy control system can adjust the gain of the sliding mode dynamically, weaken the chattering phenomenon and improve the robustness of the system.The back electromotive force(EMF) observer is established to replace the low-pass filter to avoid the phase delay.At the same time, the stability and accurate tracking of the system can be improved. The simulation results show the feasibility of the proposed method.