The invention discloses a deburring device for an aluminum alloy formwork for a building, and belongs to the technical field of grinding tools. The deburring device comprises a base, two grinding assemblies symmetrically and slidably mounted on the two sides of the base, and a control assembly used for driving the two grinding assemblies to abut against the grinding position. A motor is arranged on the base, and a transmission assembly used for connecting the motor with a first gear is arranged below the base. According to the deburring device, the base, the grinding assemblies, the control assembly, the transmission assembly and the motor are arranged, the two grinding assemblies can clamp the aluminum alloy formwork through the control assembly, and the motor drives grinding heads to rotate through the transmission assembly; the two grinding heads are arranged on each grinding assembly, so that the device can conduct deburring work on the four edges of two through holes at the same time, and the working efficiency is greatly improved; and the distance between the grinding heads is adjusted by arranging a first adjusting sleeve, a first lead screw, a limiting frame and other components, and thus the device can be used for deburring work of the through holes of the aluminum alloy formworks with different hole distances.