The invention discloses a mechanical hopper special for a building, which comprises two symmetrically arranged supports, a hopper is detachably connected between the two supports, a protection layer is arranged in the hopper, is of a three-layer composite structure, and has a corrosion resistant layer, a bonding layer and a teflon layer from inside to outside, the upper surfaces of the supports are provided with hangers, wherein a motor is arranged on one side of a support through a mounting base, a main shaft is arranged on the motor, one end of the main shaft, which is far away from the motor, is connected with two inclined columns, the two inclined columns are both positioned in the hopper, and the lower surfaces of the supports are provided with pedestals. The mechanical hopper special for the building is fast in blanking speed and uniform in blanking.