Abstract: Scour is an important cause for the failure of deep water pile foundations. Due to the directional nature of water flow, scour pits tend to be asymmetrical in shape, which may exert a more detrimental effect on the pile foundations. The ultimate soil resistance at any depth was found based on the asymmetric scour pit model to obtain the modified p-y curve. Furthermore, cosine function was introduced to characterize radial earth pressure distribution. Given the pile lateral frictional resistance modified by the scour effect, the "P-Δ" effect and the change of free section caused by scour are considered, and the pile deflection differential equation was constructed, while the horizontal bearing capacity calculation method of combined loaded pile foundation under asymmetric scour conditions was proposed. The method was verified by comparing the indoor test results and the finite element simulation results. According to the results, there was a significant difference between the horizontal bearing of pile foundation calculated by traditional symmetric scour model and asymmetric scour model. Moreover, the difference became increasingly obvious as the depth and width of scour pit on both sides of the pile increased and the slope decreased. The scour effect amplified the "P-Δ" effect and increased the difference between asymmetric scour and traditional symmetric scour calculation theories. Besides, the increase of scour depth S_d2 on the passive side made the position of the maximum bending moment continuously move down and the distance from the bottom of the scour pit decreased.