Oil-coal-water slurry as a new alternative fuel was used on diesel engines. The Multi- medium oil -coal-water slurry pump wears serious bottleneck with presence of solid coal particles. Based on VOF multi-flow model, Reynolds stress model and discrete phase model to the continuous phase and dispersed phase, the Multi- medium erosion and motion trajectory of solid particle the impact progress between solid particle and machine surface were simulated successfully. The volume content of solid phase in Multi- medium flow was lower than 10 % in this simulation model. According to the simulation result, the related parameters of solid particle, such as density and diameter, mix proportional and plunger speed of impeller greatly influenced the motion trajectory and the impaction with machine surface of solid particle. The solid particle with large mass was apt to move toward to the working surface and impacted the inside of piston shell. By contraries, little particle was liable to impact the plunger barrel assembly. The plunger speed more high, the plunger barrel assembly more erosion. The plunger barrel assembly wears with solid mix proportional.