In this paper, mathematical model of each part of the pitch as the basis, taking the power deviation of control as the input, practical experience is determined according to the fuzzy domain and fuzzy rules, system output of above the rated wind speed constant powe is the target, so the PID controller is designed for direct drive permanent magnet synchronous wind power system, Matlab was utilized to establish the simulation model of direct drive permanent magnet synchronous wind type of generator control system , and simulate it. The simulation results show that the fuzzy PID controller is able to control the variable pitch, the constant power output can be realized by the wind energy conversion system .