Abstract: The gear of CNC machine tool is an important part of the transmission system of machine tool.In order to analyze the influence of the synergistic effect of magnetic fluid and gear coating on the lubrication performance of involute spur gear, taking the magnetic fluid lubrication of involute spur gear as the research object, considering the influence of gear coating, the variation law of film thickness and pressure during the meshing process was obtained by multi grid method. The results show that the oil film thickness of coated gears is larger than that of uncoated gears. In the three special positions of meshing point, node and meshing out point, the pressure distribution of the second pressure peak with coating gear participating in meshing is smoother, which avoids the damage of large stress concentration on the gear. It can be seen that the gear coating improves the distribution of pressure and film thickness in the meshing zone, which is beneficial to the lubrication condition, and provides a reference for optimizing the tribological design of gears in CNC machine tool.