A new cutting technology on the rotating part of the interior helical surface of screw pump stator is proposed aiming at the tough condition in manufacturing metallic screw pump stator. An equation on the parameters of interior helical surface is constructed in three segments. The contact equations of three helical surfaces were constructed based on the contact condition of the rotary surface of cutting tools and on the helical surface of work piece. This way, three contact paths were confirmed and external profile of cutting tools was calculated. The geometrical shape of cutting tools was confirmed by calculating, fitting and substituting the errors. Calculated results indicated that this method is feasible, laying a theoretical foundation for the cutting process of the interior helical surface of the metallic screw pump stator.