Abstract: A mathematic model of particle erosion under inter-particle collision was established. This mathematic model includes the flow field simulation of the continuous carrier fluid under Eulerian coordinate system, the inter-particle collision simulation using the discrete particle hard sphere model under Lagrangian coordinate system and the erosion rate calculation using semi-empirical formulations. The movement simulation of solid particle and the erosion characteristics of the solid-liquid two-phase fluid in flow controller under hydraulic sand fracturing operation showed that the particles were accumulated in a narrow region from inlet to outlet of the flow controller. The erosion rate was proportional to the inlet velocity with the exponential growth. The erosion rate increased with the increase of particle diameter. The most serious erosion in flow controller occurred on the upper region of the edge with 10 mm away from the outlet.