Abstract: All the evidence, such as the Mesozoic mélange zone, the NE-NNE trending tectonic pattern formed since middle-Jurassic, and the volcanic zone in NNE direction caused by strong magmatic activities along the eastern margin of China continent, suggests the tectonic event of subduction of the Mesozoic Pacific Ocean Plate under the eastern margin of China continent. The thick remnant of Mesozoic may reveal the general sedimentation pattern of the South China Sea in Mesozoic. This paper tries to prove that the Mesozoic deposits in the eastern South China Sea belong to the western Pacific tectonic domain rather than the eastern extension of the middle-Tethys.