The site of this project is complex and the distribution of soil layers is uneven.When choosing prefabricated piles,it is difficult to cross the upper gravel soil layer and weathered bedrock layer.When choosing cast-in-place piles,loose gravel and sand layers are distributed in the shallow part of the site.The permeability coefficient of the sand layer is high,and it has a strong hydraulic connection with the surface seawater.The flow of groundwater may be affected by the rising and falling tides of seawater,which can cause erosion of the borehole wall and increase the possibility of borehole wall collapse.In response to the complex site issues mentioned above,preliminary cast-in-place pile and PHC pile tests are conducted on site.The mud loss of the cast-in-place pile test is severe,and the filling coefficient is too high.Measures such as using a 10 m steel casing and mud reinforcement to configure the viscosity coefficient still showed abnormal phenomena.The PHC pile test is conducted using the method of using a hole to assist in pile sinking for compressive static load testing,achieving the ultimate bearing capacity requirements.This article compares and designs pile types from multiple perspectives such as safety,economy,and construction feasibility,and determines the use of PHC piles,which can provide valuable design experience for engineering design.