The discrete phase solid-liquid two-phase flow model coupled with the Oka wear model was used,the particle movement velocity and incident angle were considered,the wear characteristics of particle in the multistage mixed-flow pump on the wall surfaces of the impeller and guide vane and other overflow parts were studied,and the influence of the operating flow rate change on the particle wear characteristics of the impeller and guide vane of the multistage mixed-flow pump was analyzed.The result shows that the wear generated by particle in the multistage mixed-flow pump at the impeller inlet,impeller outlet and the outer edge of the guide vane pressure surface is serious,and the surface particle wear areas of the impeller blade and guide vane blade are mainly distributed in a band-like manner.When the multistage mixed-flow pump is running under small flow condition,the particle wear of the impeller front cover plate is more serious,and with the gradual increase of the operating flow rate,the particle wear on the surface of the impeller back cover plate,impeller blade and guide vane blade gradually intensifies.The research result provided a theoretical reference for the design and optimization of solid-liquid two-phase flow multistage mixed-flow pump.