Abstract: The self-developed large field experimental simulation system for hole erosion was used to carry out the experiment on the change law of casing and fracturing materials under the erosion of high-speed sand-carrying fluid. Based on the experimental data, a dynamic model describing the erosion morphology of the inner wall of the hole was established. The rules of casing hole erosion, proppant adhesion, and fracturing material performance loss before and after the high-speed sand-carrying fluid flowing through the hole were clarified. A numerical model for the migration of proppant in high-speed erosion casing was established, and the law of proppant particle migration in casing was analyzed. The variation law of pore shape was verified. It provides theoretical support for the optimization of the volume fracturing design of horizontal wells and the reduction of the risk of fracturing tools running into the block. The experimental results show that the maximum diameter of the inner wall of the hole and the pumping pressure drop amplitude gradually increase with the increase of the concentration of the sand-carrying fluid; The thickness of the proppant attachment layer on the inner wall of the casing is gradually increasing from the wellbore heel to the toe end, which can reduce the inner diameter of the lower string by 35 mm. With the sand concentration gradually increasing, the attachment amount at the heel end of the casing gradually increases, but the attachment amount at the toe end gradually decreases; With the increase of the concentration of sand-carrying fluid sand, the breaking degree of proppant after erosion gradually becomes stronger, and the proportion of debris increases by 11%. The reduction of fracturing fluid viscosity after erosion first increases and then decreases, and the maximum reduction of fracturing fluid viscosity can reach 52%.