Characteristics of seismic facies is important for identifing submarine channels. Using 2D and 3D high-resolution seismic data, the authors are able to identify three submarine channels that developed in Pliocene, Miocene and Quaternary on the slope of the Qiongdongnan Basin. The channel that formed in Miocene mainly has such seismic characters as strong amplitude alternating with weak amplitude, reciprocal overlying, and partly developing clutter reflection. The channel that formed in Pliocene mainly has such seismic characters as high amplitude reflections, continuous or semi-continuous transversely, overlying high amplitude reflections vertically. The channel in Quaternary is characterized by classic lower cutting reflections in seismic profile, with low amplitude reflections on the whole but classic High Amplitude Reflections (HARs) at channel axis. These submarine channels should be related with the turbidity current occurring at the Lowstand System Tract (LST).