The invention discloses a composite board for controlling sedimentation of a building. The composite board is of a square structure and comprises an upper shaving board, an EPS (expanded polystyrene) board, a lower shaving board and an interface device, wherein the upper shaving board and the lower shaving board are respectively arranged on the upper side and the lower side of the EPS board; the thickness of the upper shaving board and the lower shaving board is 4-6mm; the thickness of the EPS board is 20-40mm, the interface device is arranged on at least one edge of the composite board for controlling the sedimentation of the building, and the interface device is a tenon and a mortise; the tenon is a bulge formed in a way that the EPS board exceeds the edges of the upper shaving board and the lower shaving board by 15-25mm; and the mortise is a groove formed in a way that the upper shaving board and the lower shaving board exceed the edge of the EPS board by 15-25mm. By the adoption of the composite board, the problem of non-uniform sedimentation of a base caused by the non-uniform geographical condition of a site can be effectively solved.