Abstract: The use of metal powder injection molding (MIM) technology to produce small metal parts with com-plex geometric shapes, especially for transmission parts with similar and repeated features, such as small module gears, had certain advantages. As for the selection of metal gear materials, stainless steel 17-4PH could be used in-stead of MIM technology. The mechanical properties and corrosion resistance of this material are superior to those of traditional machined gears. In this paper, according to the characteristics of stainless steel 17-4PH, gears were made by MIM process and heat treated under different conditions (after sintering, H900, H900+annealing). After quality testing, there is a slight change, which is similar to the results of traditional hot rolled plates. MIM process could make complex gears, maintain the excellent dimensional accuracy of stainless steel 17-4PH, and improve me-chanical properties.