Abstract: Based on the research of overall CNC lathe grinder mechine arrangement, how to positioning the workpiece is emphatically analyzed from the technics, the structure of center rest of lathe grinder is analyzed, the positioning error of sliding bearing is the minimum, the rolling support is not suitable; how to design the turning center rest and grinding center rest correctly to ensure the machining accuracy of parts is described, especially the structure and grinding method of grinding center rest, sliding bearing of brasses type is the key to grinding support; in practice, machining precision reach the requirements of the user drawings.