In order to study the impact of different tongue angels on the rotor-stator interaction, the internal flow of the centrifugal pump with three different tongue angels was simulated numerically by simulation of full flow field. The pump performance, internal flow characteristics, pressure pulsation characteristics and the radial force characteristic were obtained. Compared with the experiment results of pump performance, PIV test results and CFD computations, the proposed numerical methods had higher accuracy. The results showed that when tongue angel increased from 23°to 33°gradually, the head showed an increasing tendency and the high efficiency zone was widened. The maximum efficiency point was toward to the large discharge. The internal low was improved and the turbulent kinetic energy distribution was uniform with tongue angel of 33°. When tongue angel was 23°, the amplitude of the pressure fluctuation and the radial force on the impeller were significantly greater than the other two types of volute for different operating conditions. Under the low flow rate, the radial force pointed to positive Y-axis with the decreasing of tongue angels, while under the design flow rate and large flow rate, the radial force on the impeller was distributed symmetrically. Therefore, the pressure fluctuation near tongue could effectively be improved and the radial force on the impeller reduced with the increasing of tongue angels.