The invention discloses a thin aluminum plate middle grooving machining tool. The thin aluminum plate middle grooving machining tool comprises a base connected with a machine tool; rectangular positioning surfaces matched with the bottom surfaces of workpieces to be machined are symmetrically projected at two ends of the base; a strip-shaped positioning boss perpendicular to and higher than the positioning surfaces is arranged at one side edge of the base; a cutter feeding groove for feeding a cutter is formed in the base between the positioning boss and the positioning surfaces; a concave part formed between the two positioning surfaces serves as a chip removing groove for cleaning chips; and the two positioning surfaces are both detachably provided with pressing modules for pressing the workpieces to be machined. The thin aluminum plate middle grooving machining tool is simple in structure, realizes quick three-dimensional positioning of the workpieces through the positioning surfaces on the base, the positioning boss and the pressing modules, enables the machined parts to easily reach the process size and geometric tolerance requirements, and effectively improves the product pass percent.