When jet pumps are commonly used for river pumping and irrigation, the erosion of sediment in the river can easily lead to deformation and damage of the pump body, lower working efficiency, or even failure. In order to study the wear of different particle sizes on the jet pump, a three-dimensional model of the internal flow field of the jet pump was first established. Based on the discrete phase model (DPM), three types of eight types, including fine sand, medium sand, and coarse sand, were simulated and discussed. The trajectory of sand particles with particle size (0.06mm, 0.25mm, 0.35mm, 0.50mm, 0.65mm, 0.80mm, 1.4mm, 2mm) and the erosion and wear characteristics of the body, nozzle and throat of the jet pump, the result It shows that the larger the sand particle size, the larger the range covered by the trajectory in the suction chamber; the medium sand with a particle size of 0.8mm has the most serious erosion and abrasion on the pump body, and the coarse sand with a particle size of 1.4mm affects the nozzle and throat pipe. The erosion wear is the most serious.