A reducer gear for robot includes an outer contour layer and a reticulated porous base layer cladded by the outer contour layer; the outer contour layer comprises a mounting surface layer, a tooth surface layer, and a connecting surface layer connected between the mounting surface layer and the tooth surface layer and forming a complete gear outer contour together with the mounting surface layer and the tooth surface layer; the mounting surface layer, the tooth surface layer and the connecting surface layer are compact structures; the reticular porous base layer is located in a cavity formed by the outer contour layer, and fiber trabeculae in a porous grid structure are provided in the reticular porous base layer.