<p>China has consistently advocated multilateralism, emphasizing collaborative global efforts through multilateral mechanisms to address climate change. While its commitment to peak carbon emissions before 2030 was widely anticipated, the simultaneous pledge to achieve carbon neutrality came as a surprise. Given that the transition period from peak emissions to neutrality is significantly shorter than that of developed countries, this ambitious goal necessitates an unprecedented transformation of China's economic and energy systems towards deep decarbonization. Under the current Chinese system, the setting of economic growth targets by governments at various levels has had significant impacts on the output of microeconomic entities, the quality of regional economic development, and carbon emission efficiency. Drawing on panel data from 30 provinces and autonomous regions in mainland China (excluding Tibet) from 2011 to 2023, this study measures carbon emission efficiency and green finance indices using the Super Slacks-Based Measure (Super-SBM) and entropy methods, and further applies spatial Durbin and panel threshold models to examine the effects of regional economic growth targets and green finance on carbon emission efficiency. The findings reveal that green finance has played a significant role in enhancing carbon emission efficiency and that the development of green finance in one province exerts a significant positive spatial spillover effect on the carbon emission efficiency of neighbouring regions. In contrast, economic growth targets significantly inhibit the improvement of carbon emission efficiency. Furthermore, with respect to the threshold variable of economic growth targets, green finance has a significant nonlinear impact on carbon emission efficiency. The positive externalities of green finance are notably strengthened under high economic growth targets, thereby confirming the existence of the "total investment effect". Policy implications include reforming local performance evaluation systems to prioritize environmental indicators, establishing unified standards for green finance, promoting regional differentiation in policy design, and integrating digital finance to enhance transparency and effectiveness.</p>