The invention relates to the technical field of electrolysis aluminum waste treatment equipment, in particular to a wet grinding system for aluminum electrolysis cell overhauling slag. The system comprises a base; the base is provided with a wet ball mill and a negative-pressure machine; the base is fixedly connected with a support column; the support column is fixedly connected with a pipe box; the left side wall of the pipe box is fixedly connected with a bushing; an outlet end flange of the wet ball mill is connected with a circular straight cylinder; the circular straight cylinder extendsinto the pipe box, and is in rotating fit with the bushing; the right side wall of the pipe box is fixedly connected with a straight hard pipe; a filter screen is arranged in the straight hard pipe; the straight hard pipe is fixedly connected with a negative-pressure hose; the negative-pressure hose is fixedly connected with an inlet end of the negative-pressure machine; and an outlet end of the negative-pressure machine is fixedly connected with a tail gas recovery pipe. The system has the following beneficial effects: the wet ball mill is adopted for wet grinding of aluminum electrolysis overhauling slag to effectively prevent the dust harm in the grinding process; and the negative-pressure machine is used for forming negative pressure at one end of the wet ball mill to prevent enrichment of poisonous gas in a cavity of grinding equipment.