Aiming at the low speed stability of liquid mirror telescope due to the factors such as high load inertia, low control bandwidth and air convection, a high stableliquid mirror control system was designed. Choose permanent magnet synchronous motor as actuator, control part adopts the typical double-ring structurecombined with the friction torque feed-forward compensation to improve system performance to improve the system response ability and anti-interferenceability. When the system reaches the specified speed, it switches to the open-loop mode to avoid the speed fluctuation brought by the control. The double-loopmodel of the control system is established and the effect of friction torque feed-forward compensation is compared and analyzed. The experimental resultsshow that the introduction of friction torque feed-forward compensation can effectively improve the bandwidth and disturbance resistance of the control system,and the speed stability of the final liquid mirror control system can reach ±8ppm, meeting the requirements of engineering model conditions. This high stabilityresearch method has much value to popularize.