Abstract: Based on the Winkler foundation beam model and the improved p-y curve method, this paper presents a method to calculate the bending moment and displacement of a partially embedded single pile under complex lateral loading. In this method, the nonlinearity between the soil plasticity, soil resistance and the horizontal displacement is taken into account, the finite difference method for solving this problem is used, and the corresponding Matlab program is given. And then an accurate theoretical solution can be carried out easily by the developed method. In order to obtain the best stratigraphic texture from the different stratigraphic textures constructed, the displacement and the bending moment of the pile are compared. The results show that the treatment of surface soil is very important. The validity of the proposed method is demonstrated through the comparison between the calculation results of the proposed method and the field experimental results. The use of the developed method can meet the engineering accuracy requirements, and reduce the difficulty of soil parameters acquisition and the engineering cost at the same time.