The problem of bad position tracking effect in governing system of variable-speed pump-control-motor was studied. And the closed-loop Proportional-Integration-Differential (PID) control method was proposed by aiming at the motor angular displacement control. The measurement and control system of position control based on virtual instrument technology (Labview) was developed. The measurement and control system was applied to the governing system of variable-speed pump-control-motor. Then the related experiments of motor angular displacement control were carried out under open-loop control and closed-loop PID control. The result of experiments shows that the effect of closed-loop PID control of motor angular displacement is significantly better than that of open loop control.