Sediments of Paleozoic, Mesozoic and Cenozoic with a huge thickness were deposited in the Pre-Caspian Basin, which can be divided into three groups vertically, i.e Pre-salt Sediment Group, Salt Sediment Group and Post-salt Sediment Group. The Pre-salt Sediment Group is composed of the Lower Paleozoic—Lower Permian, including thick clastic and carbonate rocks. From Devonian to Early Permian, carbonates were deposited widely in the Pre-Caspian Basin, and in many palaeo-uplifts, bioherms well developed, which indicates that during this period, the offshore and shallow sea areas of the Basin belonged to shallow-water sedimentary environment with clear sea water and warm climate, with little terrestrial input of sediments from outside of the Basin. In middle and late periods of the Early Permian, the Pre-Caspian areas rose successively, the climate became dry, and the environment turned to be supratidal zone (evaporitic environment), resulting in the spread sedimentation of salts and the formation of the Salt Sediment Group (upper part of the Lower Permian) which consists mainly of halite and anhydrite. There are many salt dome structures within the Salt Sediment Group. In Late Permian and Triassic, the Basin underwent once again a large-scale transgression, and the depositional environment was shelf sea with delta locally. In Jurassic and Cretaceous, generally it was also the shelf sea (shallow sea), but there were lacustrine and lagoonal environments in different parts of the Basin. The Post-salt Sediment Group formed (Upper Permian—Quaternary) is composed mainly of clastic rocks, with carbonates locally.