Abstract: Offshore oil and gas production in China account for 20.4%and 8.7%of the nation's total respectively after development for more than twenty years.The northern South Sea contributed the most among all other waters during the 1990s but was replaced by the Bohan Bay after 1997 when the former started to decline sharply in its production.However,the production of the Bohai Bay had also started to drop in 2011,signaling a relatively production plateau or production decrease.Therefore,China needs to strengthen a strategic replacement of production and reserves in its sea waters through intensive exploration in South China Sea,especially the deep and ultra-deep waters in the continental slope of the northern part for replacement,and focusing on new domain being in the Mesozoic from the northern South China Sea to East China Sea.