Abstract: In response to the discovery of dendritic flower spots on the surface of the inner hole during acid corrosion inspection after carburizing and quenching of the planetary gear and inner hole grinding, the planetary gear was dissected and analyzed from multiple aspects such as material, hardness, and metallographic structure to evaluate the impact of dendritic flower spots on the quality of the parts. The results showed that the traces of dendritic flower spots were directly related to the uneven structure caused by the segregation of the raw material composition of the forging, and the cause was not related to the quality of the heat treatment. There were significant differences in the martensitic structure level and microhardness between the dark and light areas, and it was not recommended to use those that exceeded the national standard requirements.