In order to study the influence of volute section shape on the performance of naval centrifugal pump as the theoretical foundation of follow-up research on noise vibration characteristics of naval centrifugal pump, in the case that the volute base circle, each section area, volute tongue spiral angle, volute tongue settling angle, and volute outlet area are the same, the volute section shape is changed to design three types of volute, Type A, Type B, and Type C. Three types of volute centrifugal pumps are numerically calculated. The results show that the variation trends of external characteristics of three types of volute centrifugal pumps are basically the same. The efficiency of Type A volute centrifugal pump on the working condition of small flow is slightly low, while the efficiency of Type B and Type C volute centrifugal pumps on the working condition of large flow is low. With the increase of flow rate, the efficiency of Type B and Type C volute centrifugal pumps decreases greatly. Under the same working conditions, the variation trends of three types of volute centrifugal pumps in pressure field, velocity field, turbulent kinetic energy, and cavitation phenomenon are roughly the same. The flow field characteristics of three types of volute centrifugal pumps are different in volute tongue flow channel and volute flow channel, which indicates that changing the volute section shape mainly affects the flow fields near the volute tongue flow channel and in the volute flow channel.