Abstract: There in the South China Sea area occurred two seafloor spreadings in Cenozoic that produced the South China Sea Basin. The north and south margins were passive originally in Cenozoic, but in the late Cenozoic the Philippine Sea Plate collided with Asian Plate, which compressed the north and south margins partly. In these two margins there were left lateral and strike slip faults in late Cenozoic. We named this phenomenon Dongsha movement in the north margin and Nansha movement in the south. Therefore, we call the two margins similar-passive margins. As the left-lateral and strike-slip faults were active in the margins in late Cenozoic, fluids flowed along the faults. Oil and gas (including the methane) flowed into some favorable positions (anticline, faulting anticline and stratigraphic trap etc.), then petroliferous structures were formed. Gas hydrate resources are abundant in the gas hydrate stability zone (GHSZ) because of the NW bearing left-lateral and strike-slip faults. Therefore, we believe that the NW bearing left-lateral and strike-slip faults are very good tectonic conditions for the formation of gas hydrate resources in the north and south margins of the South China Sea area.