The invention discloses an alum crushing plant with a centralized sewage disposal function. The alum crushing plant comprises a base, hydraulic assemblies are fixedly connected to the lower surface, close to the two sides, of the base, idler wheels are arranged on the bottoms of the hydraulic assemblies, a through groove is formed in the upper surface of the base, a disposal mechanism is fixedly connected to the upper surface of the base through the through groove, the disposal mechanism comprises a shell, a frame and a driving motor, the surface of the shell is fixedly connected with the inner wall of the through groove in the base, the top of the inner wall, close to the left side, of the shell is fixedly connected with an inner threaded pipe, the inner wall of the inner threaded pipe isconnected with a screw rod in a threaded mode, the surface, close to the bottom, of the screw rod adopts polished rod design, and a first though hole allowing the screw rod to rotate is formed in theupper surface, close to the left side, of the frame. According to the alum crushing plant with the centralized sewage disposal function, the problems that in the actual use process, due to insufficient follow-up treatment of alum after the alum is crushed by rotation of blades, alum accumulation and obstruction are likely to be caused, the work efficiency is reduced and using is inconvenient aresolved.