The study of sequence microbiostratigraphy of Jahrum and Asmari formation in Shiraz, Fars, Zagros, SW of Iran and recognition of relationship between depositional sequence parameters and microbiostratigraphy 3 stratigraphic sections (Beyza, Sarvestan A, B and Estahban sections) have been selected and studied. Jahrum and Asmari formations in study area with unconformity overlying together have been exposed. Based on Field and laboratory studies such as microfossils, microbiostratigraphy, microfaceis, sedimentary environment models and sequence stratigraphy evi- dences recognized 3 depositional sequences in study area that presented during Paleocene-Oli- gomiocene. Jahrum formation consists of one depositional sequence and Asmari formation consists of two depositional sequences. Microfossils and microbiostratigraphy studies will lead to the identification of 6 biozones in the studied area. In Beyza and Estahban sections biozones 1, 2 and 3 are related to Jahrum formation and suggest Paleocene to Middle Eocene age for this formation and biozone 4 is related to Asmari formation and suggests Oligocene age for this formation. In Sar- vestan section biozones 1, 2 and 3 are related to Jahrum formation and suggest Paleocene to Middle Eocene age for this formation and biozones 4 and 5 are related to Asmari formation and these biozones indicate Oligocene-Miocene (Aquitanian) age for Asmari formation. Sequence microbiostratigraphy studies indicate that biozones of Jahrum formation are formed in DS1 and biozones of Asmari formation are formed in DS2 and DS3. Also, some relationship between depositional sequence parameters and distribution of microfossils and biozones as in the case of in SB1 and LST facies didn’t found any microfossil and we can’t suggest biozonation. In study area upper part of HST of DS1 (Jahrum formation) and some biozones related to Upper Eocene have been eliminated, for example in Estahban, Sarvestan B and Beyza sections all biozones related to Upper Paleocene to Middle Eocene and eliminated biozones