In order to simulate the heave movement of offshore drilling platform, the positional servo system which was realized on electrohydraulic proportional valvecontrol motor was designed and built. Mathematical model was established. The control algorithm was studied by numerical simulation and experiment. Fuzzy PID algorithm was realized by using method of piecewise PID. The research results show that fuzzy PID algorithm with the function of dead band correction has good stability and high precision and realizes the heave movement simulation.The system meets the performance requirements.