Aiming at the problem of speed and position control inaccuracy caused by out of step or overshoot in the practical application of stepper motor, considering the suction-type manipulator moving positioning problem, a position control system of stepper motor based on PID dual-closed-loop algorithm is designed. The system consists of STM32 controller, photoelectric encoder, slot type photoelectric switch and LV8729 driving circuit. Based on the PID dual-closed-loop algorithm, the software realization of the closed-loop control method of stepper motor position is studied. The feasibility and good control performance of the system control scheme are verified in practical application.