The utility model discloses a superposed box, comprising a base plate, the vertical side of bottom plate is provided with the atress reinforcing bar to the external fixation perpendicularly, the back-off installation is provided with the box on the bottom plate upper surface, its characterized in that, the equal outer convex of vertical side of bottom plate becomes convex and builds in the tooth,convex builds in and forms the recess between the tooth, the recess tank bottom with the vertical lateral surface of box flushes or is located the vertical lateral surface outside of box. The utilitymodel has the advantages of can be better avoid pour that the in -process produces that gas is stifled, fracture and drainage, simple structure, convenient to use, intensity is high.