In order to analyze the problem of blockage and abrasion in deep-sea mining slurry pump when conveying coarse particles,RNG k-ε turbulence model was used to solve the flow field and discrete phase model (DPM) was used to simulate particle trajectory. The distribution and movement of solid particles with different concentration and different particle size in impeller and spatial guide vane were studied. Besides,the distribution of solid particles on the blade surface and the effect of solid particles on the turbulent kinetic energy in the impeller are analyzed in detail. The results show that the head and efficiency increase by 2.9% and 1.2% with the increase of particle diameter, and decrease by 4.1% and 1.5% with the increase of particle concentration.The maximum volume fraction of particles appears near the exit edge of blade in impeller , and with the increase of particle diameter, the particles tend to shift towards the suction surface of blade, and the concentration has little effect on the distribution of particles.The maximum volume fraction of particles in the guide vane appears in the middle region of working face of the guide vane. With the increase of particle diameter and concentration, the number of collisions between particles and the wall increases, and the trajectory tends to be chaotic, which aggravates the wear condition between particles and the wall.The increase of particle diameter and concentration can reduce the flow separation at the outlet of impeller and inhibit the development of turbulent eddies, but the increase of particle concentration can also increase the friction loss between media.