Abstract: In order to further study the sound field characteristics of centrifugal pump, the slotting tests for the blade trailing edge of centrifugal pump impeller are carried out. Eighteen sets of orthogonal experiments are designed to study the influence of the blade trailing edge gap on the sound field. According to the generation mechanism of centrifugal pump noise, the re normalization group (RNG) k-ε model is used to simulate the unsteady value of full flow field of the centrifugal pump, and the turbulence pulsation action of the volute wall surface is extracted as the dipole sound source according to the FW-H equation. Based on the boundary element method the sound field of the centrifugal pump is calculated. The comparative analysis between the calculated acoustic field and the pressure pulsation of flow field is made. The results show that the pressure pulsation can reflect the magnitude of the sound pressure level to a certain extent, and the pressure pulsation fluctuates violently in the tongue area, which is the main source of noise. The slotted blade can effectively improve the uneven flow at the outlet of impeller, and has a certain positive effect on the reduction of the internal and external noise fields, and the noise reduction effect is the best when the radial slot position γ=0.90.