With the development of analytical technique, δ¹³C observations have been paid more attentions in the study of global carbon cycle. Based on the discussion  the fundamental concepts of δ¹³C in the global carbon cycle, such as δ¹³C Suess Effect, observed δ¹³C ranges of various carbon reservoirs and fractionation between them, this article introduces the analytical methods in applying δ¹³C to distinguish carbon source and sink by combining with current observational facts. The roles of δ¹³C in the study of seasonal and interannual variations of atmospheric CO₂ are discussed based on the facts that the δ¹³C from ocean is similar to that of atmosphere but that from terrestrial biosphere is much smaller than that of atmosphere. The various Keeling Plot approaches are introduced to show the achievements in analyzing the background characteristics  of atmospheric CO₂ and its applicability is also discussed. The mass balance methods using observed atmospheric δ¹³C are analyzed to represent how to only use atmospheric δ¹³C data studying the missing carbon problems. The various δ¹³C inventory techniques in the assessment of global carbon cycle, particularly oceanic uptake rate, are analyzed to point out their features and shortages, and these techniques offer no model approaches to investigate the global carbon cycle. We  stress  that the uncertainties between inventory approaches are mainly from the observational errors, not from the techniques. Finally, the prospects of δ¹³C research in the global carbon cycle for both observational and theoretical fields are also discussed, especially the model based simulations. 