To solve the problem that traditional PI controller is affected by the change of motor parameters and thus can't meet the high accuracy requirement, fuzzy PI speed controller is proposed. Current model of permanent magnet synchronous motor is built and motor speed is identified based on model reference adaptive theory. Speed adaptive law is derived according to Popov theory. Fuzzy PI controlled PMSM speed sensorless system is realized. System anti-disturbance ability is increased and dynamic-static performances are dramatically improved. Simulation results have verified the feasibility and effectiveness of this method.