In order to improve the erosion resistance of the ball-throwing sleeve ball seat in staged fracturing of horizontal wells, based on fluid mechanics and erosion theory, the paper uses Fluent software to establish the solid-liquid two-phase flow erosion model of fracturing ball seat to study the ball seat erosion wear. This paper analyzed the impact of the ball seat erosion in different angles of double cone structure and carried out the ball seat erosion test to study the erosion of three different surface materials of the ball seat. The numerical simulation shows that the erosion of the ball seat mainly occurs on the front cone surface and the maximum of erosion rate occurs at the junction of the cone surface and the sealing surface. The reason is that the diameter of the cone section gradually decreases, resulting in increase of the velocity and concentration of solid particles. With the action of the inclined surface, the increase of kinetic energy will increase the number of impacts and cuttings of the cone surface, increasing the impact force and causing wall material loss. Erosion test results show that in the erosion of three different surface materials of the ball seat, the erosion resistance of the double-coated (organic coating + tungsten carbide coating) ball seat is better than that of the tungsten carbide coating and the cemented carbide ball seat. When designing a ball seat with a double cone structure, a reasonable selection of the angle of the cone can effectively improve the erosion resistance of the ball seat, otherwise it will cause descending erosion resistance of the ball seat. When spraying the surface of the ball seat, the choice of double coating has better erosion resistance than single coating.