Abstract: The Liyue Basin is a large-scale petroliferous basin in the southern South China Sea. Based on the detailed analysis of seismic profiles, wells and trawling data from the deepwater area of the basin, with reference to the regional tectonic events and paleogeographic evolution, the key interfaces of T100, T70 and T50 were interpreted from among the seismic profiles of the basin, especially the seismic characteristics and geological significance of the T70 and T50 interfaces. It is found that during the spreading of the South China Sea from late Oligocene to early Miocene, the Liyue-Palawan Block was a shallow water environment far from the provenance. It is doubtlessly suitable for deposition of carbonate rocks. Comparing with the reefs in the Palawan Basin next to it, it is found that the seismic characteristics of reefs in the deepwater area of the Liyue Basin are typical and easy to be identified. This study clarified the development conditions of large- scale reservoirs in deepwater area of the Liyue Basin and summarized the seismic characteristics and distribution pattern of the reef deposits in the deepwater basin. Upon the basis, the exploration potential of the deep water area of Liyue basin is valuated and predicted.