Abstract: Statistical data show that more than 65% of offshore wind turbines select monopile foundation, so design and analysis of the monopile foundation are an important issue. Based on the design practice and experience of multiple offshore wind farms, the design elements of the monopile foundation are summarized. Determined by the offshore marine environment in which the wind turbines are located, the primary load on the monopile foundation is long-term cyclic load. After summarizing the methods for current laterally loaded piles, an ideal elastic-plastic pile-soil interaction model considering the effect of long-term cyclic load is established. In the case of an offshore wind farm, a monopile foundation program is designed using the above model, and comparative analyses are carried out to verify its effectiveness. The ideal elastic-plastic method is convenient to consider the effect of all the environmental loads, soil distribution and construction, and can be applied to the design of pile foundation offshore wind turbines.