Abstract：The "Belt and Road" Initiative, as an important platform for building a community of human destiny, includes the promotion of green development as one of its themes. The key to green development lies in green innovation. Employing the Difference in Difference (DID) method, the research utilizes panel data from 280 Chinese prefecture-level cities spanning the years 2005 to 2019 as its research sample. Empirical testing is conducted from both "quantity" and "quality" perspectives to examine the impact, operational mechanisms, and spatial and temporal differences of the Belt and Road Initiative on green innovation in cities along its route. The research reveals: 1) The Belt and Road Initiative effectively stimulates the increase of the "quantity and quality" of green innovations in cities along China''s routes. 2) The Belt and Road Initiative promotes the "quantity and quality" of green innovation in cities along China''s routes through the upgrading effect of industrial structure, the empowering effect of digital economy and the clustering effect of resources. 3) The Belt and Road Initiative promotes green innovation more significantly in central region cities than cities in the east and west. 4) The "Belt and Road" initiative plays a more significant role in increasing the quantity and improving the quality of green innovation in non-resource cities and megacities. The research conclusions provide important insights for propelling the jointly constructed Belt and Road Initiative toward a transition to high-quality development..