Abstract: The combined grinding machine for internal spline includes three grinding heads for processing a bore of internal spline parts. The machine clamps a workpiece and at the same time can finish grind during the bore and spline operation and boring one of its end faces. The machine has a grinding head for boring and grinding head for a side boring a spline installed in a main sliding plate which moves on a vertical shaft of the machine body. The machine has a rotary table installed in a removable working table driven by a motor unit. Both the working table and the grinding head for the spline end face are located in the machine body. The machine demonstrates high efficiency, high precision, and low equipment investment. The machine saves time for aligning and clamping procedures.