The invention discloses a cornered aluminum profile extruding die which comprises an upper die body and a lower die body. The upper die body comprises a die core. The lower die body comprises a welding chamber attached to the outer contour of a cornered aluminum profile. The upper die body and the lower die body are assembled together. A working zone used for forming the cornered aluminum profile is formed between the die core of the upper die body and the welding chamber of the lower die body. The portion, on the periphery of the die core, of the upper die body is provided with four dividing holes corresponding to the four edges of the cornered aluminum profile. A dividing bridge is arranged between every two adjacent dividing holes. The dividing holes are of a parallel inclined structure. The dividing holes are partially overlapped with the die core in the vertical direction. The overlapped area S5 of the dividing holes corresponding to the adjacent arc edge of the cornered aluminum profile and the die core is smaller than or equal to 1.5 times the overlapped area S6 of the dividing holes corresponding to the straight edges and the die core. According to the cornered aluminum profile extruding die, the die strength is greatly improved, die machining is simplified and facilitated, the production cost is greatly reduced, the phenomenon that bridge fracture occurs soon after the die is placed on a machine is avoided, the service life of the die is greatly prolonged.