In this paper, the adaptive model-following control theory applied to the position control of the hydraulic servomechanism is first presented. Second, the digital adaptive model-following PID controller is implemented on the PC-based computer with the Delphi 6.0 software. The simulated and experimental results show that the performances of the PID controller with and without the adaptive model-following control effects. The model following effects on the position control show that the performances of the PID controller can be improved by a suitable adaptation signal. Analysis of the hydraulic servo system to identify the dynamic model, this model use MATLAB / Simulink simulation software adaptive model-following PID controller. Use computer simulation model to analyze and design controllers, prove the correctness of simulation parameters.