Stable carbon isotope analysis has become one of the most effective techniques in phytoecology.Due to the differences of carboxylation efficiency,the migration rate in plants and the effects of environment factors,the stable isotope ratio (δ¹³C) is variable in different plants.In this paper, the basic theory of stable carbon isotope and its biological mechanism through stomatal,mesophyll cell conductance and leaf carboxylation efficiency were presented.We discussed how did the environmental factors influence plants δ¹³C and analyzed applications of δ¹³C in community and ecosystem on different functional groups,community canopy and tree-rings.Moreover,we gave a brief introduction of carbon stable isotope technique applied in carbon cycle.We expect this review can be a useful base to the research of carbon stable isotope in plant ecology.