The work aims to study the effect of fracturing fluid displacement and sand volume fraction on casing perforation erosion in the process of sanding fracturing. CFD numerical simulation method was used to simulate and analyze the flow field, flow track characteristics and particle trajectory in the perforated casing. E/CRC and Oka erosion models were used to simulate the erosion of casing perforated perfs and their vicinity under the condition of fracturing displacement of 5-15 m3/min and fracturing fluid sand volume fraction of 8%-23%, and the influence rules were summarized. With the increase of displacement rate, the flow velocity at the perforation increased sharply and the pressure drop reached 5.5 MPa, but a certain pressure was formed at the bottom of the pipe. The E/CRC erosion model is more suitable for the actual situation of casing perf system erosion in fracturing process than the Oka erosion model due to the consideration of the influence of particle number. The erosion velocity in the inlet direction of the perforation is obviously higher than that in the lower direction of the pipe, the erosion degree in the surrounding direction gradually decreases. The maximum erosion rate of the E/CEC model increases from 2.14×10?8 kg/(m2.s) to 5.85×10?8 kg/(m2.s). With the increase of the volume fraction of sand content in fracturing fluid, the maximum erosion rate of E/CRC model at the perforation increases from 2.21×10?8 kg/(m2.s) to 95.6×10?8 kg/(m2.s). The erosion area and erosion rate of the pipe wall near the perforation increase gradually, and when the sand ratio reaches more than 20%, the maximum erosion rate of the pipe wall near the perforation is almost the same as that near the perforation. Both the displacement and sand ratio are positively correlated with the erosion rate of the perforation, and the increase of sand ratio will accelerate the erosion of the pipe wall near the perforation. It is recommended to use low sand ratio at high sand ratio and low sand ratio at high sand ratio to reduce erosion of perforations and adjacent pipe walls.