Objective To solve the key difficulty in repairing a certain type of ship pump impeller hub and other key parts, key research is carried out on cupreous coating prepared by electric arc spraying. Methods The microstructure, microhardness, bonding strength and erosion resistance of the coating were assessed by optical microscope, SEM, microhardness tester, tensile testing machine and abrasion tester. Results The cupreous coatings were uniform in composition. The bonding strength between coating and substrate was 18.58 MPa; the microhardness was 187.5HV0.3 (higher than the substrate); and the average porosity was 4.1%. When the erosion angle was 30° and 90°, the wear mass was 0.024 g and 0.020 g respectively (the coating has excellent wear resistance). Conclusion Cupreous coating is prepared on water pump impellers by electric arc spraying technology, which not only recovers the primary dimension, but also improves the wear resistance. Meanwhile the substrate does not deform. No balance test is required. Energy and materials are both saved. It is estimated that the life span will extend for 3 times. This technology provides a new concept and method for repairing key copper parts of large and new equipment.