In the actual production of the CNC machine tool, the poor adjustment of each axis servo parameters would affect the machining accuracy of the machine tool. In order to improve the matching of servo parameters of each axis in multi-axis machining, the calculation method of contour error in three-axis CNC machine tool was proposed, and the influence of servo parameters of feed system in three-axis CNC machine tool on contour error was analyzed, and the method of matching servo parameters between two feed axis was then proposed. The machining of double helical gear was taken as an example, the actual machining path data before and after optimization of parameters were compared. The result show that the contour error of the double helical gear reduces from 300 μm to 100 μm. The matching of servo parameters of each axis can greatly improve the machining accuracy of CNC machine tools.