Abstract: The paleo-spreading-ridge of the eastern South China Sea, striking in NE50°, lying between the Eurasian plate and the Pacific plate (Philippine Sea plate), is about 240 kilometers long from east to west and bordered with theManila Trench, the North Luzon Trough and the West Luzon Trough to the east.Based on previous studies, this paper is devoted to the discussion of the subduction time, subduction depth and dynamic process of the paleo-spreading ridge.After 16Ma, the paleo-spreading-ridge of the South China Sea was passively subducting along theManila trench, forming the structural pattern of the middle segment of theManila Trench.The depth of subduction was between 200-300km, with slab tears happened at about 100km, which resulted in the difference in subduction angle on both sides of the paleo-ocean-ridge.The subduction of the paleo-ocean-ridge is quite significant to the research of South China Sea's tectonic evolution in the future.