A comprehensive study of 24 key deepwater oil-gas-bearing basins of the world, mainly from the Atlantic deepwater and the Neotethyan domain was carried out by the authors, including those in the Gulf of Mexico, eastern Brazilian continental margin, West African passive continental margin, Mid-Norway continental shelf, Northwest Shelf of Australia, South China Sea, Bay of Bengal, and the Mediterranean(Nile Delta).Forming ages, tectonic settings, and depositional environments of the main reservoirs were summarized, and the distribution patterns discussed.Results show that the main reservoirs of the deepwater oil-gas-bearing basins in the world were formed in the time of Cretaceous and Peleogene. The age of main reservoirs in the Atlantic deepwater basins show a distribution pattern of older in the north and younger in the south, whereas the main reservoirs in the Neotethyan deepwater basins are dominanted by the Peleogene.