Among carbon pools of terrestrial ecosystems, the soil carbon storage is the largest and has the longest resident time. Since the soil carbon storage and its cycling are affected by the land use practice, effective land use management can result in the role of soil as a carbon sink. The process of soil carbon sequestration is the change of dynamic balance of soil organic carbon (SOC), which is critical for revealing the process and regulatory mechanism of soil carbon cycle. This paper presents and summaries the application of stable and radioactive carbon isotopes (δ¹³C and ¹⁴C) in the regeneration of longterm carbon dynamics process of ecosystem(such as the historical pattern of C₃/C₄ vegetation) and in SOC cycling. The application of isotopic techniques in the studies of SOC source and cycling, soil CO₂ flux change and component difference, isotopic enrichment, etc. is also discussed. In addition, the fundamental issues related to SOC dynamics are outlined and the major topics for isotopic tracer of SOC dynamics in future are proposed in the paper.