Celestite mineralization has more than 60 Km outcrop at Bangestan anticline, Northwest Behbahan, Ahwaz. The structure and form of mineralization occur as stratiform, following the lower massive limestones and upper shaly limestones of the Asmari Formation. Pseudomorphism of sucrosic celestites with gypsum, anhydrite and calcite inclusions is an indication of Sr2+ substitution for Ca2+ in calcium sulfates and calcium carbonates. The late diagenetic and epigenetic effects on the celestite mineralization is shown by the zebra and vein-type celestite, the mosaic crystals with 1200 angles, the fine-grained euhedral celestite into the coarse-grained anhedral celestite and the spary calcite and celestite, cross cutting the first generation celestite. The Sr/Ba ratio of the celestite is 7500 times greater than sea water. A strong positive correlation exists between SrO and SO3 (0.998). Trace element data are compatible with these late diagenetic effects.