Abstract: The horizontal displacement control of a monopile with a large diameter is the main difficulty for offshore wind turbine.A new type of large-diameter monopile with steel-wings set in the region of the pile near the mudline,named the wing-monopile,is investigated.With the help of wings,the shallow soil reaction in front of the pile is taken full advantage of;and the horizontal bearing capacity of the monopile is enhanced.The relationships between the horizontal load and the horizontal displacement are fitted by adopting an exponential model and a 4-order polynomial model based on data obtained by numerical simulation.The simulated results show that the 4-order polynomial model is more accurate than the exponential model;because of the setting of steel-wings,the horizontal displacement and the maximum moment of a pile are decreased observably;the horizontal bearing capacity of a pile is increased markedly and the increment is influenced by the setting-position of the wings.The method to improve the horizontal bearing capacity of steel-pile by the wings can be used for other types of a small-diameter pile of foundation structure of the offshore wind turbine so as to decrease the construction cost.