In the design of small and medium-sized high pile wharf，PHC prefabricated pile has good corrosion resistance and high bearing capacity，which is widely used，but its penetration ability and impact resistance are weak.In the coastal area of Weifang，Shandong Province，there is a silty sand layer with shallow burial depth，large thickness and high blow counts，which makes the pile penetration more difficult.Therefore，the PHC-steel pile composite pile is proposed.Based on the pile foundation modification design of a 5 000-ton multi-purpose wharf project in river estuary area，the rationality of the scheme is comprehensively demonstrated from the aspects of pile foundation design，finite element analysis，static load test and high strain detection.Furthermore，the reduction factor of pile end bearing capacity is proposed，which provides a certain basis for the calculation of vertical bearing capacity of similar projects in this area.