In the field of ecosystem carbon storage service evaluation, numerous models and tools have emerged. However, quantitative comparisons of the evaluation results produced by these models have not been made. To analyze the differences and effectiveness of these models, this study employs two ecosystem service assessment tools, the InVEST and ARIES models, to evaluate carbon stock in the central urban area of Chongqing. The results indicate that the carbon density of the central urban area is 92.99 t/hm² (116.88 t/hm²), and the total amount of carbon storage is 505.03×10⁵ t (639.58×10⁵ t) from the InVEST model (ARIES model). Among different land cover types, forests exhibit the highest carbon density, and both croplands and forests serve as the primary carbon pools in the region. Regarding altitude gradients, carbon density increases with altitude, while carbon stock first increases and then decreases. Both models reveal a consistent spatial distribution pattern of regional carbon storage, characterized by "low in the middle, high around the edges," although the distribution forms differ significantly. The differences in evaluation results between the two models are attributed to variations in carbon density data and evaluation units. The InVEST model focuses on land cover types as the evaluation units, distributing carbon stock by land cover types, while the ARIES model integrates land cover types with grid units, distributing carbon stock in patches. The InVEST model's results reflect the carbon stock levels of various land cover types, whereas the ARIES model further reveals the spatial heterogeneity of carbon stock within the same land cover type. The ARIES model's results are more effective, providing robust support for regional carbon sequestration policy formulation.