Abstract: In order to prepare a chromium nitride film with excellent friction properties, the state-space model predictive control is used to continuously and stably control the nitrogen flow. In this paper, the target voltage control method is used for rapid feedback control of nitrogen flow. The hysteresis effect data of nitrogen flow and target voltage are collected through reactive magnetron sputtering experiments. The mathematical model of the controlled object is obtained by the system identification method, and the state-space model is used to predict the algorithm used for control and compared with PID control. The simulation results show that the adjustment time of the statespace model predictive control is 16 seconds faster than that of the PID control, and the step disturbance is seven times smaller than that of the PID control. The model predictive control has a better control effect. In the experiment, the state-space model was used to predict and control the nitrogen flow. The friction coefficient of the prepared chromium nitride film was tested to be 0.7, and the experiment achieved the expected effect.