Abstract: The use of CFD-ACE for numerical simulation of hydrostatic bearing is based on engineering practice, and the Numerical Simulation is carried out under fluctuation load. According to the results, the characteristics of the bearing capacity and stiffness of the oil film under fluctuation load is analyzed compared with the theoretical formula. The result indicates that the film thickness, bearing capacity and stiffness have different effects under Fluctuations in different frequency load. This research provides a basis for the reliability design of the hydrostatic bearing system.