The invention discloses a die for gear forging. The die comprises an upper die base, a lower die base is arranged at the bottom of the upper die base, clamping blocks are welded to the two sides of the bottom of the upper die base, clamping grooves which are connected with the clamping blocks in a clamped mode are formed in the two sides of the top of the lower die base, and heat insulation platesare welded to the two sides of the upper die base. According to the die, the upper die base, the lower die base, the clamping blocks, the clamping grooves, the heat insulation plates, a handle, a first round groove, a second round groove, a third round groove, a fourth round groove, a fifth round groove, a cylinder, a pouring opening, a heat dissipation groove and a heat dissipation hole are arranged and cooperate with one other, so that the problem that an existing die is low in practicability is solved, in the process of forging a gear through the die, a hole can be reserved in the surfaceof the gear at the same time, so that secondary hole opening is not needed, the machining progress of the gear is improved, the machining time of the gear is saved, the labor amount of a worker is reduced, the cost of gear machining is reduced, and therefore, the die is suitable for popularization and use.