The Dariyan Formation (Aptian) is one of the important hydrocarbon reservoir rocks of Khami Group in the south west of Iran. As exact evaluation of reservoir rocks is possible through of microfacies and their sedimentary environment analysis, by this way, two subsurface sections (X1 and X2 wells) of Dariyan Formation in Salman oil field, located in 144 kilometers far from south of Lavan Island (Persian GulF) with the mentioned aims was considered and evaluated. This Formation in Salman oil field in subsurface section 2S48 well, with 105 meters thickness andin subsurface section 2S2 well with 123 meters thickness include limestone with limestone with interbeds of shale. Extended microscopic assessment of deposits of the Dariyan Formation in mentioned sections led to recognition various facies in mold of four facies groups related to environments, open marine (A), bar (B), lagoon (C) and tidal flat (D). Its worthy to mentioned in subsurface section X1, four facies group are recognized, while in subsurface section X2 only the facies group that related to open marine environment was recognized. The vertical changes survey and comparing it with recent and old sedimentary environment indicate that the facies of Dariyan Formation in understudy sections have been appeared in a carbonate shelf and most of the facies were deposited in deeper part of the carbonate platform.