Abstract: To accurately research the hydrostatic bearing oil film performance,based on the computational fluid dynamics(CFD) and finite difference method,velocity slip phenomenon of the oil film micro-flow in hydrostatic bearing clearance and its influence on bearing performance are investigated. The sensitivity parameters are defined to evaluate the impact of velocity slip on the bearing performance. Based on the conventional assumptions of the oil film flow, the conventional Reynolds equation is modified by introducing Navier-slip boundary condition. Modified Reynolds equation is solved by finite difference method,and the performance parameters such as bearing capacity are deduced using the method of trapezoidal integral formula. The parameters of sensitivity are used to make a quantitative and qualitative analysis.Resultsshow that bearing performances such as the distribution of oil film pressure,bearing capacity,dynamic stiffness and oil cavity flow have a certain sensitivity for velocity slip. The maximum cavity pressure decreases with the increase of slip length,to a certain extent,the load capacity and oil flow of the bearing are improved; however,the dynamic stiffness of the hydrostatic bearing is reduced at the same time. The maximum sensitivity of quality flow to velocity slip is 100%.