the optimum control model was deduced so as to enhance the precision and to improve the dynamic characteristic of electro hydraulic position servo system. The optimal Q matrix was obtained through optimum. The P matrix was deduced from Riccati equation and the optimal control for electro dynamic position servo system was obtained. The analysis on the dynamic before and after optimum was obtained through numerical emaciation.The analysis result shows that optimal control can not only decrease the surpass capacity of the system but also improve its respond speed.