CNC lathe is highly automated machine tools, CNC lathe main drive system is characterized by: (1) CNC machine high speed and large enough power, to meet the need of high efficiency machining; (2) CNC lathe spindle speed change fast, reliable and general can automatic transmission; (3) the spindle should be high enough stiffness and rotation accuracy; (4) should CNC lathe spindle speed range is very wide, such as the high speed cutting of aluminum alloy material, there is almost no limit restrictions, highest numerical control lathe spindle speed depends on the main drive system of transmission components allow limit (such as numerical control lathe spindle bearings allow limit speed), while the lowest speed according to the requirements of machining hard processing material such as stainless steel. Now in our factory design and production of DS11 type full-function CNC lathe as an example, introduces the design of main drive system.