In this research, Biostratigraphy and depositional environment of the Asmari Formation in south flank of Khaviz anticline was studied. The thickness of Asmari Formation in this section is 283m that consists of alternating thin, medium and thick bed to massive Limestones. Study of benthic foraminifera led to recognition of 28 genera and 25 species. According to the vertical distribution of foraminifera, four assemblage zones were identified. Based on vertical distribution of the identified foraminifera and assemblage zones, the age of Asmari Formation in the studied section is Oligocene (Ruplian- Chattian)- Early Miocene (Aquitanian-Burdigalian). Based on field and laboratory research, 10 microfacies in the Asmari Formation were recognized. These microfacies have been deposited in three major depositional environments including shallower part of the open marine, barrier and lagoon. As a result a homoclinal ramp is suggested for deposition of the Asmari Foamation.