The gas hydrate (known as “combustible ice”), a new methane resource exists in a special area, is a white ice-like crystalline solid formed from a mixture of water and natural gas under the condition of a low temperature and high pressure. Great amount of which lay inside the shallow sediment layers of continental slope and continental ridge in the deep sea. The hydrate deposit has the characters of environmentally clean, high energy density, widely distributed with a large scale, shallow burred and optimal physical and chemical mineralization condition, as a result, it is regarded as an optimal resource to replace oil and gas.

　　This paper first reviews the history of gas hydrate anomaly discovery on the northern continental slope of the South China Sea and is then focused on the gas hydrate studies on the seismic characteristics, the mechanism of formation and reserve for modeling, mineralization rule for preliminary resources assessment. It is attempted to clue and guide future gas hydrate survey in the sea area and the gas hydrate prospect prediction. Conclusions of this study are as follow:

　　a. Compared with the latest hydrate drilling result from ODP Leg 184, the analysis of regional tectonics revolution in the Miocene, the sedimentation of middle Pliocene, recent geomorphology and formation condition of hydrate suggests that the geological tectonic setting in the sea area is much favorable for the formation of hydrate.

　　b. The conditions of temperature (T) and pressure (P) are examined at the BSR layer on the real seismic profiles, the results of the integrate studies of T-P condition for hydrate formation are much in agreement with the results of concerned international studies.

　　c. Based on the studies of geological, geophysical and geochemical data, the analysis of mineralization characteristics of hydrate indicates there are prospect area and optimal layer for gas hydrate deposit in the northern continental slope of the South China Sea.

　　d. It is worthy to mention that Dongsha Plateau and Xisha Trough can be a pilot area for study on physical and chemical characters of hydrate at passive continential margin; on the contrast, the eastern edge of the Bijia basin can act as active margin study case.