Abstract: Large-scale sand fracturing is a necessary means in the efficient exploitation of shale gas/oil. However, in the process of fracturing operation, the sand carrying fluid and proppant easily causes scouring and wear to production strings, especially the casing perforation system, which damage the wellbore integrity and deformation to affect the subsequent fracturing. For this problem, taking the actual construction conditions and perforation technology of an oilfield in western China as an example, the structural parameters of the downhole string were measured and the wall thickness reduction model of casing perforation suitable for large-displacement sand fracturing in horizontal well section was established. With software ANSYS-FLUENT, the casing perforation erosion under the conditions of different displacements, sand content and perforation sand-passing quantity in the process of sand fracturing was simulated and calculated. The influences of three parameters on perforation erosion and expansion were analyzed and the prediction chart of the influences of three main control factors on perforation erosion and expansion was established. The perforation erosion images after fracturing construction were obtained with the downhole eagle perforation logging technology. The logging chart results were compared with the downhole eagle perforation data. The error between the established numerical simulation calculation charts and the real logging data was about 5%, indicating that the simulation charts were the valuable reference.