In this paper, based on CORTEX M4 master control chip GD32F450I, path planning of millimeter precision PTZ is completed by using cubic polynomial method, so as to reduce impact and vibration in motion and improve the motion accuracy of the PTZ. Using a double-loop control algorithm based on position loop and velocity loop control method, the position motion precision of the millimeter precision PTZ can be controlled quickly. For the pitch movement of the PTZ, it is also necessary to effectively eliminate the backlash error caused by the load torque by means of fluctuation difference compensation. The control accuracy of the millimeter precision PTZ can reach 0.004deg (azimuth) and 0.006deg (pitch).