The longitudinal morphology of continental slopes contains significant geological information, the variations of which are thought to be related with the long-term interaction of sedimentary and erosional processes. Based on a series of 2D seismic profiles crossing the northern South China Sea margin, we have utilized a curve fitting procedure to investigate the morphology of continental slopes and recognized three types of continental slopes, including the concave-up, planar and sigmoidal. Concave-up slopes develop within the Yinggehai-western Qiongdongnan area and are thought to be dominated by rapid sediment supply. The central Pear River Mouth area also has concave-up slopes, but they are mostly attributed to the progradation of shelf-edge deltas as well as the erosion of a giant submarine canyon. The sigmoidal slopes are mainly distributed on the two flanks of the Pearl River Mouth area, which resulted from the shaping process of ocean currents and internal waves. A certain type of continental slope tends to have its own stratal stacking pattern, shelf-edge trajectory trend and characteristic depositional systems. Investigation of modern slope morphology can help build up the conduit-sink models, thus providing useful guidance for deep-water hydrocarbon exploration on ancient buried slopes.