Abstract: Based on a practical offshore wind power project, the influence factors of axial bearing performance of monopile in heterogeneous layered foundation are studied by numerical method and optimization suggestions are put forward. The results show that the axial force of pile increases slowly from the pile top to the mud surface, and decreases significantly with the increase of buried depth under mud surface. The proportion of each component of axial bearing capacity changes gradually with the increase of load applied to pile top, and the internal and external side friction resistance shows a trend of "dislocation play" with the increase of load applied to pile top. The external side friction increases evenly with the increase of pile depth in space, while the internal side friction mainly is mobilized in the lower part of monopile. Pile diameter and buried depth have great influence on axial bearing capacity. The grinding of pile body can effectively improve the axial bearing capacity of pile, especially the external side friction resistance, and reduce the axial force of pile body with grinding. In practical engineering, pile diameter and buried depth should be determined by comprehensive consideration of various factors, and the external surface of monopile near the pile end can be treated with grinding to improve the axial bearing capacity of the monopile.