Abstract: Submarine canyons are widely developed in the continental slope of the South China Sea,which seriously affects the safety of offshore facilities such as drilling platforms. Based on the high-precision survey data from autonomous underwater vehicles （AUVs） in the canyons of area D of the continental slope in Qiongdongnan Basin,South China Sea,the characteristics of the submarine topography and geomorphology,the geological conditions of the shallow surface layer in the study area are analyzed. A total of 7 canyons of different scales are identified. The geomorphological units in the canyon area are divided into canyon walls,canyon channels,and erosion-accumulation areas at the bottom of the canyon. Based on the strength reduction method,the stability of the submarine slope in the study area is calculated using finite element software,and the stability of the submarine slope in the study area is quantitatively evaluated.

Key words: Qiongdongnan Basin, submarine canyon, stability of submarine slope