Abstract: The stand age can affect plant and soil carbon storage through tree species composition and soil nutrient cycling processes in forest ecosystems. This paper summarized the characteristics of plant and soil carbon accumulation during the successional development stages of natural forests and plantations. With increasing stand age, the total carbon storage of plant and soil in natural forests reaches a steady state, whereas plant and soil continue to accumulate carbon in plantations. The carbon storages of plant and soil in all age classes of plantations are lower than those in natural forests, especially in near-mature and over-mature forests. The plant carbon storages of natural forests differ from those of plantations at different stand age. It should be noted that stand age and canopy area are the main factors affecting the plant carbon storage of natural forests. For plantations, stand age and forest management practices, including seedling recruitment and forest thinning, are the main factors affecting carbon storage. Furthermore, there are differences in soil carbon storage between natural forests and plantations with increasing stand age. In particular, stand age, species diversity and hydrothermal conditions are the main factors influencing soil carbon accumulation in natural forests, whereas stand age, forest site conditions and forest management practices are the main factors influencing soil carbon accumulation in plantations. The distribution of soil aggregate carbon, litter input, and soil microbial activities can influence soil carbon stability in forest ecosystems. In conclusion, future research should focus on how climate change influences soil carbon stability in both natural forests and plantations.