Abstract: There is a complex correlation between the mechanical structural parameters and operation performance of water pumps. Reasonable matching between impeller geometric parameters and volute structural parameters directly affects equipment efficiency. In this paper, numerical simulation and experimental verification are carried out to systematically analyze the influence laws of key parameters such as blade number, outlet angle and volute radial clearance on the operation performance of water pumps. The numerical results show that the efficiency of the 6-blade impeller can reach 85.2%, and the head peak is 32.8 m when the blade outlet angle is 25°. Experiments verify the accuracy of the numerical simulation. The efficiency of the optimized prototype reaches 85.3%, which is 4.1% higher than that of the baseline scheme. The results provide a theoretical basis for the optimal design of water pumps.