Abstract: An adaptive fuzzy sliding mode control strategy is proposed to address the nonlinearity, time lag and time-varying parameters of vacuum chamber air pressure control in magnetron sputtering coating process. The time-varying FOPDT characteristics of the vacuum system are revealed by establishing a system dynamics model and adopting the forgetting factor recursive least squares method to identify the parameters. The integral sliding mode surface and fuzzy logic compensation mechanism are designed to construct an adaptive controller to realize the dynamic suppression of nonlinearity and disturbance. Simulations and experiments show that compared with the traditional PID and conventional sliding mode control, the proposed controller improves the response speed by 35.7% and reduces the overshoot by 62.5% in the pressure interval of 0.1−10 Pa. The accuracy and robustness of air pressure control for the coating process are improved.