Abstract: Southwestern of East China Sea Busin differ from other part of bausin in evolution，tectonic movement、 sedi-mental environment etc.
Southwestern evolution of East China Sea Basin may be divided into four stages,i • e • faultdown,downwarp,lift and draping.Sediment interupted 15-20M.Y. during lift movement later Eocene. This proccess did not undergo in other part of oasin. Second,it was eroded over 1000 meters during elevating move-ment later Eocene. This scene never took place in other area of basin, Third characteristic is mainly marine facies enviro-nment during Eogene yet transgressive develpment highest peak at Eocene, marine water area about 8000km². Northeastern of the basin is continentai deposit. Mudston rock of high pressure may be distributed in the middle part of research area. The oil and gas potenliai of restarch area may be best in the basin.

Key words: Eost sea Basin, Tectonic movement, oil and gas enrichment