Abstract: Elevated atmospheric CO₂ affects plant photosynthesis process and biomass accumulation, furthermore alters the distribution of photosynthetic carbon (C) above- and below-ground. The formation and turnover of soil organic carbon (SOC) depends on the input of photosynthetic C, so the change of plant physiology and metabolism caused by increasing CO₂ concentration will further affect the balance of SOC pool. Therefore, stable isotope ¹³C technique is powerful for clarifying the influence of elevated atmospheric CO₂ on C cycling in plant-soil system, including the distribution of photosynthetic C among plant organs, and the transformation and accumulation of photosynthetic C in soil. This review summarized research focused on the effects of elevated atmospheric CO₂ on C cycling in terrestrial ecosystems based on ¹³C natural abundance or ¹³C tracing technique, including: 1) isotopic fractionation effect in plant photosynthesis; 2) the distribution of photosynthetic C in plant organs; 3) the transformation and stabilization of photosynthetic C in SOC driven by microbial process. Clarifying the above processes and controlling mechanisms is essential to predict long-term influence of elevated CO₂ on C cycling and evaluate the source-sink function of SOC in terrestrial ecosystems.