Abstract: The new airport project in Sanya planned by government of Hainan Province of China, is located at Hongtangwan of Sanya City, that is, to build an offshore airport with an area of a 28 square kilometers. The construction of this project makes great contribution to the economic development of Hainan Province, which plays an important role as a strategic fulcrum of the Maritime Silk Road. The site investigation of the land reclamation is based on the CPTU tests, which are widely used in the evaluation of characteristics of soils, but there is no related experience of offshore projects using the CPTU tests. An offshore CPTU test is carried out in the land reclamation of Sanya New Airport using the CPTU system developed by Institute of Geotechnical Engineering, Southeast University. The test results are analyzed and compared with the field data and laboratory tests. It is shown that the CPTU tests, as relatively mature in-situ tests, are applied to offshore engineering practice.