With the development of large-scale reservoir port construction in inland mountainous areas，it is necessary to carry out reinforced high fill construction to obtain more land space. The interaction between wharf pile foundation of frontier operation platform and soil in reinforced fill area has become an important factor affecting wharf structural safety. Taking an overhead vertical wharf in the Three Gorges Reservoir area as an example，we discuss the law of soil arching effect behind piles in reinforced high fill area through indoor model test，and it is proved that the reinforcement effect is beneficial to improve and enhance the stress of pile foundation. By the finite element analysis method，the influences of reinforcement arrangement，slope of fill area and physical and mechanical parameters of soil on soil arching effect and pile foundation stress are systematically compared and analyzed，and suggestions are put forward for optimizing the design of pile foundation in reinforced high fill area.