Sandy sediments extensively developed in the west coast of Hainan Island. The TL dating data for the sandy sediments of Qiziwan section showed that the stratum which belongs to the upper Basuo Formation of Upper Pleistocene deposited between 32.1±3.30~10.30±1.30 ka BP. The stratum of Qiziwan section ranged from aeolian to weak soilforming to aeolian to alluvial to aeolian from bottom to top, and this was proved by technical analysis including sedimentary structure characteristics, grainsize characteristics, scanning electron microscope etc. The arragement of sedimentary facies reflects that the stratum was mainly consisted of thick aeolian facies, mixd by some thin fluvial facies (layer Ⅱ) and weak soilforming aeolian facies (layer Ⅳ) which were caused by the shortterm climate changes. This is heteropic deposit of Basuo Formation, which is considered as alluvial—pluvial deposition in this area. We infer that continental shelf of the South China sea broadly emerged by the climate change in the last Ice Age, accompany by the frequent sanddrift activities which caused sandy desertified process and provided an important sources of aeolian deposits in the west coast of Hainan Island.