Tunnel foundation for island-tunel project of HZMB using a variety of foundation forms, including PHC rigid pile composite foundation, high pressure jet grouting pile composite foundation, sand compaction pile composite foundation and natural foundation. In this paper, the composite foundation and natural foundation settlement calculation methods and parameters selected is analyzed with Code for design of building foundation, Technical code for ground treatment of building and Technical standards and commentaries for port and harbor facilities in Japan, which indicates that the sand compaction pile composite foundation settlement calculation should refer to Technical standards and commentaries for port and harbor facilities in Japan, PHC rigid pile composite foundation settlement calculation should follow the Code for design of building foundation GB50007—2012, high-pressure jet pile composite foundation settlement calculation should comply with Technical code for ground treatment of building provisions of cement mixing pile, natural foundation settlement should consider stress history e - lgp settlement calculation method and secondary consolidation coefficient for settlement calculation should match the actual stress test. This article outlines settlement caculation methods and parameters selection principle of different foundation treatment methods for the HZMB island tunnel works, to provide reference for similar projects in settlement calculations.