[Objective] The carbon storage and carbon sequestration potential of new afforestation in the hilly region of the Loess Plateau were quantitatively assessed， in order to provide theoretical support for optimizing forest carbon sink management and carbon sink trading in this region and similar regions. [Methods] Taking Youyu County， Shanxi Province as the study area， data from artificial afforestation projects from 2012 to 2024 were systematically compiled. The biomass method and the Logistic growth curve model method were used to estimate the carbon density and carbon storage of different carbon pools （including biomass， dead organic matter， soil organic carbon， and total carbon） in the new afforestation area， and the future carbon sequestration potential was predicted. [Results] ① From 2012 to 2024， the carbon storage （calculated by carbon） increased from 6.18×10⁴ t to 2.49×10⁶ t， representing a 40.29-fold increase. The inclusion of baseline soil carbon storage outside the original boundaries was the core driving factor of the increase. ② If the contribution of baseline soil carbon storage from the new afforestation was excluded， the carbon storage in 2024 would be 5.05×10⁵ t， with biomass carbon storage accounting for 93.19%， making it the main carbon pool. The total carbon density in 2024 would be 14.98 t/hm²， lower than that of existing forests nationwide. In terms of tree species， the carbon storage proportion of Pinus sylvestris var. mongolica in 2024 was 79.57%， making it the primary carbon-sequestering species. The carbon density of mixed coniferous-broadleaf forests and P. sylvestris var. mongolica was significantly higher than that of other tree species， indicating that these two tree species had greater carbon sequestration potential locally. ③ By 2060， the carbon storage and carbon density were projected to reach 4.78×10⁶ t and 1.42 t/hm²， respectively， and the carbon density would be slightly higher than that of forests nationwide. P. sylvestris var. mongolica would remain the main carbon-sequestering tree species， but mixed coniferous-broadleaf forests would have greater carbon sequestration potential due to their higher carbon density （210.46 t/hm²）. [Conclusion] The new afforestation in Youyu County has achieved remarkable carbon sequestration effectiveness. In the future， the forest carbon sink capacity can be further enhanced through measures such as optimizing tree species structure and transforming shrublands， and the value of carbon sink ecological products can be realized by leveraging the national carbon market.