Abstract：Available geological and geophysical data obtained around the northern continental margin of the South China Sea were used to compile the synthetic geotransect from the eastern margin of Indo-China Peninsular, through Xisha Trough, the northern continental slope of the South China Sea and Henchung Peninsular in Taiwan to the Philippine Sea. This geotransect is about 1800 km in length. The topography and morphology, geophysics, structural geology and time-space evolution reveal the configuration of the ocean-continent boundary and the interaction in the northern continental margin of the South China Sea, which is significant for understanding the tectonic framework and deep water petroleum geology in the northern margin of the South China Sea.