Abstract: The formation of cracks in pressing female dies by powder metallurgy were investigated by die materials, heat treatment process, and metallurgical structures, the structure of gear hub die by powder metallurgy and the design reasonability of pressing dies were discussed, and the crack formation reasons were analyzed and corrected through the detailed data of pressing female dies in this paper. In the results, the material selection and heat treatment process have no connection with the crack formation, the inappropriate design of die structure is the primary reason for the crack formation. Improving the pressing female die structure of gear hub could increase the service life of die, reduce the cost of die, and keep the production running smoothly.