<p>As a crucial component of the green financial system, green credit serves as an effective tool to facilitate the economy’s transition to low-carbon practices. However, the boundary and strengthening conditions of its impact on carbon productivity still require further investigation. In this context, this paper constructs a theoretical model incorporating heterogeneous production sectors and employs the spatial panel models to examine the impact characteristics of green credit on carbon productivity from both theoretical and empirical perspectives. The findings indicate that green credit enhances carbon productivity, and regional carbon productivity exhibits spatial spillover effects. This impact of green credit is significant only in regions with weak economic and climate policy uncertainty. Further threshold effect analysis shows that the strengthening effect of green credit on carbon productivity depends on economic development, government innovation support, and marketization degree. This study offers new insights into the economic and environmental effects of green credit and provides empirical references for the design and implementation of optimized green finance policies.</p>