China’s “dual carbon” agenda shows its proactive approach to global carbon reduction. This study uses a spatial panel model to examine financial development and carbon emissions in China. It also examines how financial development thresholds affect carbon emissions, using research and development intensity and technical market development level as key variables. The results show that: (1) Finance in China is concentrated in the Circum-Bohai Sea and eastern coastal regions, with lower levels in the central and western regions. China’s high-carbon zones are mostly in the northwest and northeast. However, low-emission areas are mainly in the south. (2) Financial development increases local carbon emissions and decreases neighboring carbon emissions. However, it still hinders carbon emissions in the region. (3) Financial development promotes more carbon emissions in the northwest than in other regions, possibly due to additional variables. (4) Financial development initially increases regional carbon emissions when R&D intensity is the threshold variable, but this effect fades. When technological market development is the threshold variable, financial development’s impact on carbon emissions has gone from insignificant to major to insignificant promotion.