The large deep-sea area from the southwestern Qiongdongnan Basin to the eastern Dongsha Islands,within the continental margin of northern South China Sea,is a frontier of natural gas hydrate exploration in China.Multiform of deep-sea sedimentations have been occurred since late Miocene,and sediment waves as a potential quality reservoir of natural gas hydrate is an most important style of them.Based on abundant available data of seismic,gravity sampling and drilling core,we analyzed the characteristics of seismic reflection and sedimentation of sediment waves and the occurrence of natural gas hydrate hosted in it,and discussed the control factors on natural gas hydrate accumulation.The former findings revealed the deep sea of the northern South China Sea have superior geological conditions on natural gas hydrate accumulation.Therefore,it will be of great significance in deep-sea natural gas hydrate exploration with the study on the relationship between deep-sea sedimentation and natural gas hydrate accumulation. The large deep-sea area from the southwestern Qiongdongnan Basin to the eastern Dongsha Islands, within the continental margin of northern South China Sea, is a frontier of natural gas hydrate exploration in China. Multiform of deep-sea sedimentations have been created since late Ceocene , and sediment waves as a potential quality reservoir of natural gas hydrate is an most important style of them. Based on abundant available data of seismic, gravity sampling and drilling core, we analyzed the characteristics of seismic reflection and sedimentation of sediment waves and the occurrence of natural gas hydrate hosted in it, and discussed the control factors on natural gas hydrate accumulation. The former findings revealed the deep sea of ​​the northern South China Sea have superior geological conditions on natural gas hydrate accumulation. Herefore, it will be of greater significance in deep-sea natural gas hydrate exploration with the study on the relationship between deep-sea sedimentation and natura l gas hydrate accumulation.