<p>Global urbanization has significantly driven land use transitions, with substantial consequences for the global carbon cycle. In spite of the importance of understanding the carbon effects of land use transitions, the underlying mechanisms and suitable assessment methods remain uncertain. The study introduces a new framework to evaluate the carbon effects of land use transitions, demonstrated in the Huainan mining area, China. This study’s findings indicate that: From 2000 to 2020, the carbon source and emission increased by 2.01 × 10⁷ t, spatial pattern of lower western and higher eastern levels. Concurrently, carbon sink increased by 2.53 × 10³ t, primarily in the central and southeastern fringe areas. Over the same period, carbon storage decreased by 1.8 × 10⁶ t, few areas of high carbon storage. Land use transitions’ various dimensions exert distinct influences on carbon effects. Among these factors, land use intensity (LUI) demonstrates the most substantial explanatory power for carbon source, carbon sink, carbon emission, and carbon storage. Land use structure (LUS) correlates positively with carbon sink, while Land use intensity (LUI) is strongly negatively correlated with carbon sinks. Land use dynamics (LUD) significantly negatively correlated with carbon storage. The lowest carbon emission (3.38 × 10⁷ t) occurs in the ecological protection scenario, while the highest carbon storage (3.00 × 10⁷ t) is observed in the cultivated land protection scenario. The proposed assessment framework offers valuable scientific guidance for land spatial planning and carbon reduction strategies in other regions.</p>