In this investigation Dariyan Formation with the age of Lower Cretaceous (Aptian- Albian) were studied for microfacies analysis and diagenesis trend in the surface section at Kuh-e Siyah Anticline and subsurface section Sabzpushan well number 1. Based on petrographical studies 12 microfacies identified which are belonging to 5 facies belt, such as: intertidal, lagoon, shoal, shallow open marine and deep open marine. The observed facies patterns indicated a homoclinal carbonate ramp depositional environment. Important diagenetic processes were observed in Dariyan Formation including cementation, bioturbation, dissolution, physical and chemical compaction and replacement processes such as dolomitization and silicification. With the observations of transmitted and cathodoluminescence microscopes different generations of spary calcite cement were recognized that suggest diagenetic alteration of Dariyan Formation occured in a burial setting. Prosities in these sections are secondary, including vugy, fracture and channel types.