This study investigates the causal relationship between green digital finance and technology diffusion using panel data from 35,532 'citing city-cited city' pair observations from 2002 to 2015. It applies and extends the classic spatial Dubin model with a dual-weighted boundary and distance to account for different spatial spillover effects of administrative boundaries and geographic distances. The main findings are: (1) Green digital finance shows significant and considerable spatial stimulus effects, particularly in terms of spatial diffusion across cities. A slight cumulative phenomenon is revealed for different technology diffusion durations. Green digital credit, investment, and support have better stimulating effects on technology diffusion. (2) Digital economy and market integration are effective mechanism pathways during this stimulating process of green digital finance on technology diffusion. Digitalisation innovation has a better mechanism effect than others. (3) Considering the direction of technology diffusion, the diffusion effect from the east-region cities was better than that from the central-west-region cities. The study also finds that green digital finance promotes technology diffusion by fostering a digital economy through the level of digitisation, innovative capability and communication cost, and by promoting market integration. The results support the hypotheses that green digital finance overcomes localisation barriers and promotes technology diffusion, and that green digital finance promotes technology diffusion by fostering a digital economy and promoting market integration. The study concludes that green digital finance has significant spatial stimulus effects on technology diffusion, particularly across cities, and that digital economy and market integration are effective mechanisms for this process. The study also finds that the diffusion effect from east-region cities is better than that from central-west cities.This study investigates the causal relationship between green digital finance and technology diffusion using panel data from 35,532 'citing city-cited city' pair observations from 2002 to 2015. It applies and extends the classic spatial Dubin model with a dual-weighted boundary and distance to account for different spatial spillover effects of administrative boundaries and geographic distances. The main findings are: (1) Green digital finance shows significant and considerable spatial stimulus effects, particularly in terms of spatial diffusion across cities. A slight cumulative phenomenon is revealed for different technology diffusion durations. Green digital credit, investment, and support have better stimulating effects on technology diffusion. (2) Digital economy and market integration are effective mechanism pathways during this stimulating process of green digital finance on technology diffusion. Digitalisation innovation has a better mechanism effect than others. (3) Considering the direction of technology diffusion, the diffusion effect from the east-region cities was better than that from the central-west-region cities. The study also finds that green digital finance promotes technology diffusion by fostering a digital economy through the level of digitisation, innovative capability and communication cost, and by promoting market integration. The results support the hypotheses that green digital finance overcomes localisation barriers and promotes technology diffusion, and that green digital finance promotes technology diffusion by fostering a digital economy and promoting market integration. The study concludes that green digital finance has significant spatial stimulus effects on technology diffusion, particularly across cities, and that digital economy and market integration are effective mechanisms for this process. The study also finds that the diffusion effect from east-region cities is better than that from central-west cities.