Based upon the features of nannofossil composition, distribution, abundance and diversity, the fossil-bearing sediments exposed by five drill holes in the offshore area of southern Hongkong can be divided into the upper Middle Pleistocene, the Upper Pleistocene and Holocene. There were two palaeoclimatic stages in the Holocene in this area according to fossil palaeoecologic and sedimentation analyses: the temperature-rising stage and the warm stage. The latter involves two temperature-falling periods, which could be the major factor causing sea-level fall during that time.