Abstract: With the advantages of low cost, short construction period and relatively small foundation disturbance, the bucket foundation has become one of the important foundation forms of offshore wind power in China. Because of its complex foundation structure, the classical method for foundations can not accurately evaluate the vertical bearing capacity of the bucket foundation. In this study, the lower bound method of finite element limit analysis is used to transform the bucket-soil interaction into an inequality constraint condition between the bucket-soil friction and the undrained shear strength of the soil, and a lower bound solution program for the vertical bearing capacity of the bucket foundation is established. On this basis, the effects of the non-uniformity of the soil strength, length-diameter ratio of the bucket foundation and friction between the outer wall of the bucket and the soil on the vertical bearing capacity of the bucket foundation are analyzed, and a formula for calculating the vertical bearing capacity of the bucket foundation considering the above factors is proposed.