Abstract: The mechanical structural parameters and operating performance of a water pump have a complex relationship. The proper matching of impeller geometry and volute structural parameters directly affects the equipment efficiency. Through numerical simulation and experimental verification, the influence of key parameters such as the number of blades, outlet angle, and volute radial clearance is systematically analyzed. Numerical calculation results show that the efficiency of a 6-blade impeller can reach 85.2%, with a peak head of 32.8 m at an outlet angle of 25°. Experiments verified the accuracy of the numerical simulation. The optimized prototype achieved an efficiency of 85.3%, a 4.1% improvement over the baseline design. These results provide a theoretical basis for the optimized design of water pumps.