The oil film thickness of static pressure workbench varies with the change of working load, temperature, viscosity and other timevarying condition factors, which will make the thickness deviate from the target value and then affects the accuracy of the workbench. Therefore, the research on oil film thickness adjustment method has greatly practical significance for ensuring the machining accuracy of parts. In view of the static pressure workbench with variable frequency speed regulation, the formation principle and characteristics of oil film thickness were analyzed and two kinds of oil film thickness control models were established by using the method of working condition coefficient and the cubic interpolation respectively. The influences of varying working conditions were taken into overall consideration such as the structural size of the worktable, the external load and the viscosity of the oil when adjusting the oil film thickness. The electrical eddy current system DT3300 and Siemens CNC system 840DSL were employed to build an integrated experimental platform for the measurement and adjustment of oil film thickness. Through the regulating test of a practical static pressure workbench with a diameter of 2 500 mm, the rationality and reliability of the two kinds of control modes are verified, which provide reference for the research on oil film thickness of other static pressure workbench.