In order to study the influence of the volute section shape on the performance of naval centrifugal pump as the theoretical basis for the subsequent research on the noise and vibration characteristics of naval centrifugal pump. Under the premise of ensuring the base circle of the volute, the area of the first eight sections, the outlet position of the volute, the outlet diameter of the volute and the center height are the same, the section shape of the volute is changed, and three volute types of A, B and C are designed respectively. The centrifugal pump was numerically calculated with clear water as the medium. The results show that the external characteristics of the centrifugal pump of the three types of volute are basically the same. The efficiency of type A volute centrifugal pump is slightly smaller under the condition of low flow rate, while that of type B and C volute centrifugal pump is small under the condition of large flow rate. With the increase of flow rate, the efficiency of type B and C centrifugal pump decreases greatly. The static pressure distribution, streamline distribution, velocity distribution, turbulent kinetic energy distribution and gas volume fraction distribution trend of the three types of volute centrifugal pumps under the same working conditions are roughly the same. The change of the passage near the impeller tongue is different from that in the volute passage, which indicates that the change of the volute section shape mainly affects the flow field at the impeller outlet and the volute channel.