A soil separation device for building waste comprises frames arranged on two sides and a plurality of driving shafts installed in the two frames. A plurality of polygon prisms are distributed at intervals on each driving shaft in the axial direction and protrude out of the driving shaft. The length of the polygon prisms is smaller than the distance between the polygon prisms, the polygon prisms of the adjacent driving shafts are arranged in a staggered and meshing mode, soil dropping gaps are formed between the adjacent driving shafts, two ends of each driving shaft are installed in the two frames respectively, and a driving mechanism is arranged in each frame to drive the driving shafts to rotate. Due to the fact that the polygon prisms are arranged on the driving shafts, on one hand, the soil separation device can beat block building waste with soil on the surface in a rotating mode, on the other hand, the soil separation device has the effect of removing the soil in a gnawing mode due to ridges on the surfaces of the polygon prisms, and soil on the block building waste can be quickly separated accordingly.