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The Carboniferous was a critical period of extreme environmental changes in Earths history.This study presents the δ13C and δ18O records of whole rock from the Carboniferous (Serpukhovian-Gzhelian stage)Bashisuogong Formation,Biegentaw Formation and the Lower member of Kangkelin Formation in Sepabayi area,Southwestern Tianshan Mountain.The isotopic pattern exhibits that there are four main δ13C and δ18O excursions.The curve represents three ice ages and an organic carbon burial event during Carboniferous when compared to the litho-and bio-stratigraphy.They exhibit low δ13C values at the bottom and a sharp shift to positive,and a significant change of δ18O values in Bashisuogong Formation suggesting that the first and greatest glaciation occurred between the Devonian and Carboniferous boundary.The isotopic excursions can be further evident in the framework ofplumeworldmodel.Model simulations indicate that the proportion of continental melt water and oceanic water is about 2∶5.The negative values of carbon isotope in the Lower member of the Biegentaw Formation revealed another ice age.This event may result from a cease of oceanic biological productivity.Approximate 10‰ of carbon negative anomalies in reef limestone of the Kangkelin Formation imply that the effective hydrocarbon reservoirs suffered partial oxidation.Meteoric waters and continental weathering also caused the obvious phenomenon.A slight but continued increase of δ18O values about the Carboniferous-Permian boundary may suggest another glacial event following the late Carboniferous minimum.