Abstract: As a new type of marine foundation, bucket foundation has been increasingly applied in the offshore wind turbine engineering. Its stable service performance is closely related to the interaction between bucket foundation and marine soil. In order to evaluate the undrained horizontal bucket foundation-soil interaction efficiently and accurately, a modified p-y spring method is proposed, based on the conventional p-y spring method for pile foundation. The three-dimensional finite element analyses are compared with the p-y curve recommended by API standard, and the p-factor and y-factor are introduced as double correction parameters. In addition, a parametric analysis is also carried out on common single-layer and layered clay geological conditions in the ocean, varying the soil shear stiffness coefficient G_max/s_u, failure shear strain\gamma _\textf^\textpand other factors. The NGI-ADP soil model is used to effectively represent the nonlinearity property of soil. It is found that the y-factor can be significantly affected by multi-layer soil. The p-factor is generally within the range between 1.38 and 2.08. Furthermore, the modified p-y spring method has shown good adaptability to the actual project site conditions based on an application case study. And for some working conditions the application of the modified p-y spring method also extends to consider the bucket foundation-soil interaction under multiple degrees of freedom.