Abstract: It is still a hot problem to calculate the force of laterally loaded piles in engineering. At present, the p-y curve method is mostly adopted in international engineering specifications. Generally speaking, soft soil is different from sandy soil. The unconfined strength index combined with the empirical formula is generally adopted for the soft soil, and the internal friction angle combined with the empirical formula for the sandy soil. At present, there is no unified method. Based on the Winkler foundation beam model, a unified p-y curve based on the tangent modulus is proposed, which takes into account the non-linearity of pile-soil interaction and can be applied to the calculation of horizontally loaded piles under various geological conditions. At the same time, the parameters required by the proposed method are discussed and studied, and a relatively simple and scientific parameter acquisition method is determined. On the basis of the research results, a case study of a complex soil layer is carried out, and the applicability and accuracy of the proposed method in complex geological conditions are verified through numerical analysis, providing a new method for engineering design.