A stepping motor position closed loop control system was designed, which adopts displacement sensor to examine the position of the load. The system’s hardware constitute was given here, and the pulse control project was given at the same time. It uses the high-speed pulse output of PLC to export the adjustable frequency pulse. The adjustment of the frequency based on the error of initial value and actual value. On one hand, it can realize fast and accurate position control. On the other hand, it can overcome the weakness of losing step. Thus makes the system have better control function.