Abstract: At the time of its deposition, the Qianjiang Formation of Paleogene in the Jianghan Basin was an elevated saline basin, so its geochemical aspects of formation of oil and gas are different from those in other basins of continental deposits in the eastern part of China. Primarily based on organic geochemical data, together with geological and paleontological materials available, the characteristics of oil and gas formation in saline lake deposits are examined, best expressed in low organic content, high ratio of oil trans formation and apparent OEP of n-alkanes. Evolution of organic materials is divided into four stages according to total hydrocarbons/organic carbon; the threshold depth and temperature for oil and gas formation are supposed to be at 2,200 meters and 90℃. Diagrams of depth of burial are used in the study of evolution of source rocks and determination of the main stage of oil generation Oil and gas migration and comparison of oil sources in the basin are also discussed.