To solve the problem that the regular PID speed controller is effected by the change of motor parameters and thus can't meet the high accuracy requirement, this paper proposes the fuzzy self-adaptive speed controller which can adjust the proportional revision factor Cp, integral revision factor Ci and differential revision factor Cd of PID controller on line according to the speed difference and the change rate of speed difference. It is applied to the direct torque control system of speedless sensors, which improves the response and the steady state accuracy. Simulation results have verified the design effectiveness.