In the context of global economic shifts and escalating environmental concerns, the emergence of financial technology (fintech) stands out as a critical determinant in shaping sustainable economic pathways. Based on the actual conditions in Jiangsu Province, this study constructs a green economic development evaluation system that encompasses five subsystems: society, economy, energy, environment, and technology, comprising 28 indicators. By employing the entropy-weight TOPSIS method and a coupling coordination model, the paper analyzes the development of Jiangsu’s green economy from 2013 to 2020. The research results indicate the following: (1) During the study period, the coordination among subsystems in Jiangsu Province generally progressed well. By 2020, the coordination index surpassed 0.65, indicating a moderate level of coordination overall. (2) The main pressures on Jiangsu’s green economic development stem from energy and environmental factors. (3) There is a clear gap between technological advancement and economic expansion, underscoring the need to strengthen investments in green technology and infrastructure. Addressing this gap is critical for mitigating low energy efficiency and promoting a resilient green economy. By revealing the multiple impacts of financial technology on green economic development, this study provides important theoretical foundations and empirical support for the dynamic relationship between technological innovation and sustainable development. The findings not only offer new insights into the role of fintech in driving green economic transitions but also provide valuable references for policymakers in formulating strategies to promote investments in green technology and infrastructure.