The small modulus gear hobbing machine was removed of drive gears and worm wheelworm, and both hob spindle and workpiece spindle directly were connected directly with the motor shaft. Geometric error and thermal error were main error coming from the small module hobbing machine. For the case of that, a new type of motorized spindle is designed. The form of the spindle motor being behind the spindle bearing was used, which led to the reduction of radial size of spindle bearing position, the heat dissipation cased by bearing friction and the reduction of the influence of electrical machine emitted heat made deformation of bearing. The form of the hydrostatic bearing was used on spindle bearing, which improved the abrasion resistance and the rotation accuracy of the spindle bearing. Production efficiency and machining accuracy of the small modulus gear hobbing machine are improved by the designed motorized spindle.