Abstract: The pre-salt strata in south uplift of Pre-Caspian basin is of advantageous conditions for hydrocarbon accumulation. Two sets of high quality source rocks and three sets of carbonate reservoirs with good reservoir properties are found in its Middle Devonian-Upper Carboniferous. This paper studied its petroleum geological conditions and reservoir-forming controlling factors, in view of the regional structure and sedimentary evolution integrated with the latest drilling data. The result shows that the distribution and maturity of the source rocks control the framework of “gas in the west and oil in the east” in this area; the large-scale paleo-uplift belt controls the development of the carbonate rocks and reefs, and the weathering leaching effect greatly improves the reservoir property in the carbonate reservoir of the Visean-Bashkirian (KT-2), which control the hydrocarbon accumulation