The accuracy of the spindle is directly related to the rotation accuracy of the spindle components. The surface geometry error and surface roughness of the joint of spindle, bearing, gear and other parts are related to the contact stiffness. The more accurate the contact surface shape and the smaller the surface roughness, the smaller the contact deformation, that is, the higher the contact stiffness. Therefore, certain technical requirements must be put forward for the design of the spindle, which mainly includes the dimension tolerance, shape tolerance, surface roughness, surface hardness and other contents of each mating surface of the spindle, and should be marked accurately and reasonably on the spindle part drawing.