Abstract: The East China Sea is located at the conjunct region between the continental and oceanic plates, and the tectonic movements in the sea area controlled by the activities of these two plates. The sea floor attributed to continental crust can be divided into four structural levels at the lower crust above the granite layer, and have experienced three geological stages as: the transform margin during the Mcsozoic time, the passive margin of Paleocene-Miocene, and the active margin in the late Eocene-Quaternary. The tectonic movements of different natures in each stage resulted in tectonic frameworks in which the alternative compressional and extensional tectonic regines would be developed. The stress fields in the area would vary with their different positions in the sea area. From east toword west and the old to young, compressional and extensional stressfields alternated or overlapped one to another, constituting the complex tectonism of the area.