Abstract: The primary investment sector for IFDI is manufacturing. As the global leader in manufacturing, China’s carbon emissions from this sector account for over half of the total emissions in society. The manufacturing industry is the main battlefield for energy conservation and carbon reduction, which played a crucial role in achieving the "dual carbon" goals. Investigating the spatiotemporal patterns of carbon emissions in the manufacturing sector along the Yangtze River Economic Belt (YREB) and their interaction with IFDI holds significant theoretical and practical value for achieving the "dual carbon" goals and attracting high-quality foreign investment. This paper integrated the Environmental Kuznets Curve hypothesis and the Pollution Halo hypothesis into a unified theoretical framework, based on the New Economic Geography theory. Using spatial quantile regression, three-dimensional kernel density estimation, bivariate spatial autocorrelation tests, and GS3SLS spatial simultaneous equation models, the study conducted an in-depth analysis of the spatial patterns and interactive effects of manufacturing carbon emissions and IFDI in the YREB. The results revealed that: (1) Both manufacturing carbon emissions and IFDI exhibited a spatial pattern characterized by a gradient decreasing from downstream to midstream and upstream regions. (2) There was significant spatial clustering of manufacturing carbon emissions, IFDI, and their interactions. (3) There was a significant mutual inhibition effect between manufacturing carbon emissions and IFDI. Overall, the introduction of IFDI could curb manufacturing carbon emissions, while reducing manufacturing carbon emissions could enhance the attraction of IFDI. Robustness checks, spatial heterogeneity tests, and endogeneity tests all supported the above conclusions.