Vertical liquid static pressure guide rail is the key equipment of nanometer Numerical Control (NC) precision machining. The movement speed of hydrostatic guide rail is not only influenced by the machining precision of parts, but also on the bearing performance of oil film. So it is very necessary to determine the best working speed of the machine tool guide rail. The nano-surface grinding machine static pressure guide film is taken as an example. Through the Fluent simulation of fluid, it was gotten by analysis of the track speed and maximum pressure, minimum oil film pressure, oil film bearing capacity: quantitative in relative static state, the oil cavity pressure field is with symmetrical distribution; velocity of rail increases, which will produce imbalance of oil film bearing; oil film pressure on the rail to verify the capacity is very small, which can be neglected; the nano NC grinder best hydrostatic guide way movement speed range is 0 m/s to 0.1 m/s and 0.3 m/s to 0.5 m/s; in the speed range, the guide rail bearing performance is quite good. This study provides some theoretical significance for the selection of working parameters of closed hydrostatic guide for precision machine tools.