Abstract: Geo-tectonic environment of the continental slope of the South China Sea is favorable to the formation of gas hydrates. Diapir structures, submarine slides and active faults are well developed. Due to the thermal effect of deep mantle rising, the South China Sea has a high background value of heat flow, and is rich in geothermal resources. In this paper, an option was proposed to use submarine geothermal as a source to heat seawater for decomposition of gas hydrate. A preliminary process of production is described in the article. Production of gas hydrates by traditional thermal excitation consumes large amount of energy, and the cost is too high. Using geothermal to exploit gas hydrates in the South China Sea with the technology designed in this article is much more cost efficient and feasible.