Abstract: A Carboniferous strontium isotope evolutionary curve was constructed based on22data of strontium isotope analyses of unaltered marine rock samples collected from a Carboniferous section at Ma-jiaoba,Jiangyou,Sichuan.The variation trend of this curve is consistent on the whole with that of the contemporaneous strontium isotope curves constructed using samples from Huishui ,Guizhou,China,and from North America,showing the importance of strontium isotope curves for the chronostratigraphic cor-relation of marine strata.According to the correlation of these curves,this paper discusses the chronostrati-graphic division of the Carboniferous section in Majiaoba and the sea level changes.