In order to improve the processing performance of abrasive water jet and prolong the service life of nozzles,based on EulerEuler approach and discrete particle model,the threephase flow in the nozzle of abrasive water jet was studied by computational fluid dynamics (CFD).The physical model of abrasive water jet nozzle was established,and the correctness and accuracy of the model was verified by comparing with the experimental results in literature.According to the userdefined particle sphericity,the effect of particle sphericity on the particle exit speed and the wall erosion rate were analyzed by CFD.The simulation results show that with the increase of jet pressure and particle sphericity,the outlet speed of the particles is increased and the wear in the nozzle is decreased.With the increase of abrasive flow rate and particle sphericity,the outlet speed of the particles is increased and the wear in the nozzles is increased.With the decrease of particle size and the increase of particle sphericity,both the outlet speed of the particles and the wear in the nozzle are increased.The aspect ratio of depth and width during the cutting process is increased with the increase of jet pressure,decreased with the increase of transverse velocity and target distance,and increased with the increase of particle sphericity.