Because nearly five years have passed since China's Belt and Road Initiative (BRI) was implemented, there is an urgent need to explore whether it has significantly promoted provincial green economy development. Focusing on the primary provinces along its route, this study uses a GML index based on SBM directional distance function to evaluate provincial green total factor productivity (GTFP) and quantitatively analyses the BRI's net effect on provincial GTFP. The results indicate that provincial GTFP development is relatively good, with technological progress being its main driving force, there are significant differences between the regional GTFP development along the Silk Road Economic Belt (SREB) and the Maritime Silk Road (MSR), and the BRI has played a significant role in promoting provincial and two regional GTFP. R&D investment inhibits provincial GTFP development while it is not significant. There is a U-shaped relationship between economic development and GTFP, a negative correlation between the current provincial economic level and GTFP. Trade between provinces and countries along the route has a negative effect on GTFP. To promote GTFP development, the provinces should value foreign trade, improve innovation mechanism, cultivate talents and actively embed in the BRI construction.