The sand with carbonate content is characterized by porosity，irregular particle shape，easy cementation，easy breakage and so on while its origin，structural mechanism and engineering mechanical properties are quite different from ordinary quartz sand，especially the carbonate content has a significant impact on the bearing capacity of pile foundation. In this paper，the influence mechanism of carbonate content on the bearing capacity of pile foundation is summarized，and the calculate method recommended by API which is the internationally recognized pile design code and Imperial College（ICP）are introduced. Finally，the influence of carbonate content on the bearing capacity of pile foundation is calculated through an engineering example of an artificial island project in Saudi Arabia.