In recent years, offshore wind power has developed rapidly, the installed capacity has increased continuously, and the traditional single pile foundation is under heavier load. Therefore, the composite pile foundation composed of single pile foundation and bucket foundation (friction wheel) installed on the periphery of the pile body is gradually adopted to ensure the safety and stability of the fan during its service. In order to study the bearing capacity of composite pile foundation, the horizontal bearing capacity of composite pile foundation was studied by ABAQUS finite element software, and its bearing capacity advantages compared with traditional single pile foundation were analyzed, and further optimization design was carried out. The results show that under the same loading condition, due to the existence of friction wheel, the displacement at the mud surface of pile body and the bending moment of pile body are greatly reduced, and the horizontal bearing capacity is obviously better than that of single pile foundation. The diameter and height of friction wheel in composite pile foundation have obvious influence on its horizontal bearing capacity, but its thickness has limited influence on the horizontal bearing capacity of composite pile foundation. It can be seen that the bearing capacity of composite pile foundation is obviously better than that of single pile.