In a shale gas gathering and transportation station, the sand particles that are not separated by the upstream desander will cause erosion damage to the vertical separator. In response to this problem, based on the field data of a production well in the Changning area, the corresponding mathematical model and vertical separator geometric model were established. On the basis of the software FLUENT, the effects of different gas velocity, particle size, and sand mass flow on the erosion of the separator and the motion of particles were simulated. The corresponding results show that the erosion scar of the inlet baffle presents a ring shape, and the maximum erosion position on the wall changes with the increase of gas velocity. The erosion rate of the inlet baffle is proportional to the sand flow rate and geometrically related to the gas velocity; the maximum erosion rate of the vertical separator is 520 μm/a under the conditions of 6 kg/d sand input; the separation efficiency decreases with the increase of particle size and speed.