Abstract: According to the structural features of the plastic part and the molding characteristics of a combination of “metal powders + ABS”, an injection mold based on hot runnerwas designed for energy saving rings. The reasonable mold structure was determined on the basis of the investigation on the formed part, gating system, side-core pulling mechanism and temperature control system, Through the use of a hot runner gating system, and a cooling water channel based on straight pipe and septate well, the part achieved a dimensional tolerance within a basic dimension of±0.4 %, and their tolerance of angle and surface roughness reached 0.5° and Ra0.8 μm, respectively.