Tectonic process and structural functions are important geological factors which control the formation and existence of gas hydrates. Favorable channels for gas flowing and incompact reservoir with high porosity for gas hydrates can result from complicated structural movements in continental slopes. Dongsha Islands and adjacent area have favorable conditions for gas hydrate formation as they have large water depth, large sediment thickness, high sedimentation rate, and high organic matter. The recent study also lets us find geophysical identification sign BSR of gas hydrate. Using the present study results, we have done the relationship study between the gas hydrate occurrence and the fault fracture, mud volcano, and submarine landslide. This study will help find out the distribution characteristics and the evolution of gas hydrate in various structural fields, and make a contribution to the resource assessment of gas hydrate.