Forestation was considered as one of the most effective and ecological approaches for increasing carbon sink, and then to promoting atmospheric CO₂ absorption and mitigating climate change. It was also one of the key measures in forestry engineering and ecological restoration. In this paper, Jiangxi Province was selected as the typical study area of red soil hilly region - one of the primary plantation areas in Southern China. The Mountain-River-Lake program since 1980s in Jiangxi Province is a typical successful program of ecological restoration in red soil hilly region, which increased the forest coverage of Jiangxi by 28.55% through implementation of greening barren hill, reforestation, and the Grain for Green Program. This study applied TGTRing and InTEC model simulation, scale transformation from plot to transect and region, field investigation and sampling, dendrochronology method based on tree-ring information, forest inventory data, and carbon budget model, to discuss the effects of forest age and human activities on net primary production (NPP) and carbon sequestration, and then to analysis the annual variation of plantation NPP and carbon sequestration. We try to depict the relations among forest age and NPP through the growth curves of main planting tree species, and then the carbon sequestration of plantation were simulated. The purpose of this paper is to evaluate the carbon effects of forestation, and the carbon regulation service of ecological restoration. The results showed that: 1) The NPP simulations for main planting tree species by tree-ring suggested that the NPP value of Masson pine (P. massoniana), Slash pine (P. elliottii) and Chinese fir (Cunninghamia lanceolata) rises rapidly with the increased forest age and reaches to the peak value in 10a (1058 g m^-2 a^-1), 10a (901.09 g m^-2 a^-1) and 11a (1305.67 g m^-2 a^-1) respectively, and then decreased to stable level in 42a (87.2 g m^-2 a^-1), 42a (156.0 g m^-2 a^-1) and 40a (33.0 g m^-2 a^-1); 2)The NPP trend of plantation from 1980 to 2007 in Jiangxi Province were decreased rapidly before and then increased slowly, which responded the lower quality of plantation. Although the forest coverage increased from 26.98% to 60.05% mainly contributed by the enlarged plantation area, the forest volume per hectare were relatively lower especially for the plantations, because the forest is dominated by secondary natural forest, and middle- aged even young-aged plantation; 3) The variation of carbon sequestration presented as steady trend in the first 8 years before 1988 (2.19-2.37 gC m^-2 a^-1) since the beginning of Mountain-River-Lake Program. It then increased rapidly reach to 8.02 gC m^-2 a^-1 at the thirteen years, and followed by relatively lower increasing rate; 4) The influences of precipitation and temperature on plantation NPP were showed unobvious. However, the elevation greatly impacts the absolute value of NPP, but not the variation trend. In addition, the NPP increased with higher slope; 5) Validated by tree-ring estimated carbon sequestration value and station observed net ecosystem production (NEP) value, we found that modeled NEP shows good consistency than annual net increasing carbon sequestration; 6) The potential carbon sink thorough tree planting is higher than other planting patterns. Furthermore, closing for reforestation showed unobvious advantage in carbon sequestration service.