Abstract: Introduces a six degree of freedom motion simulation manipulator of known as the Stewart platform, controlled and driven by an electrohydraulic system. Based on an analysis and discussion of the system specifications, structural characteristics and working principle, the mechanical structure and computer control system are designed. The inverse kinematics of the six degree motion platform is provided. Intelligent PID algorithm is used in the position control servo system with asymmetrical cylinder. Experimental results show that the precision in position control can reach within 0 1 mm. Actual running proves that the performance of the motion platform meets fully the technical specifications. It has a high load to weight ratio as well as a fine control accuracy.