Abstract: The sleeve sealing ball seat is one of the important components in the multistage fracturing process of horizontal wells. The erosion and wear of the surface will decrease the sealing performance of the fracturing ball and the ball seat. This leads to pressure leakage during the fracturing process and fracturing failure. In this paper, combined with the actual ball seat materials and working conditions during the fracturing process, the erosion tests of ductile iron and tungsten carbide materials under different erosion speeds, angles, and mortar concentrations are carried out. Then the erosion test results were analyzed by mathematical fitting, and a set of erosion models suitable for sliding sleeve setting ball seat materials were innovatively established. For the first time, this paper combines the erosion model obtained from the experiment and the computational fluid dynamics (CFD) with Fluent software to simulate the erosion of the ball seat. Based on the simulation results, the morphology of the sliding sleeve seat ball after erosion is predicted. Through analysis of the test and simulation results, it is showed that the erosion rate of tungsten carbide material is lower and the wear resistance is better under the condition of small angle erosion. This research can offer a strong basis for fracturing site selection, surface treatment methods, and prediction of failure time of ball seats.