The present invention relates to an injection molding stepping motor, including an injection molding stator assembly and a rotor assembly, wherein the injection molding stator assembly includes a stator iron core, a front framework, a rear framework, a stator winding, a front lining ring, a rear lining ring and a mounting bracket, the stator winding is wound in a groove of the stator iron core into which the front framework and the rear framework are inserted, the front lining ring and the rear lining ring are mounted on two sides of the stator iron core, the stator iron core is fixed on the mounting bracket, and the front lining ring and the rear lining ring each adopts a structure which is formed by punching and laminating thin plates with different inner diameters. Compared with the prior art, the present invention has the advantages of reducing axial magnetic flux leakage of a motor and improving the moment of the motor.