To better understand the performance of a hydrostatic spindle in motion, the impact of oil film slip on the load capacity, stiffness and dynamic stiffness of the spindle is studied. Based on the velocity slip boundary conditions, the stress characteristic equation and the liquid flow equation of the hydrostatic spindle are formed into a coupled equation system that is used to numerically analyze the load capacity stiffness of the spindle system. The spindle properties and oil film characteristics are considered in the initial stage of oil film. From the simulation results, it is concluded that the occurrence of oil film slip results in the increase of the bearing capacity and stiffness, with a highest increase rate of approximately 40%. The existence of the slip phenomenon is confirmed in the oil film flow process of a spindle system, with a slip length of approximately 3μm determined by the simulation results, which are verified by the measurement of the axial stiffness of the spindle. This study explores a new method for the analysis of the static and dynamic performance and the determination of the dynamic stiffness of a hydrostatic spindle.