The invention relates to a method for repairing a high Cr cast iron dredge pump impeller, and belongs to the technical field of engineering ship equipment. The method for repairing the high Cr cast iron dredge pump impeller is characterized in that bead welding is adopted to conduct recovery to the size of the position of a water sealing belt on the high Cr cast iron dredge pump impeller, it is guaranteed that an original gap between the water sealing belt and a lining board restores, and pump efficiency of the dredge pump is achieved. The method has the advantages that work efficiency of equipment is high, the working life and the replacement cycle of the equipment are long, and replace cost of spare parts is reduced; and the repairing method is convenient to operate, economical and practical, high in execution efficiency and pertinence, good in welding quality and the like.