Given that the ecological environment of the areas along the Belt and Road is increasingly exasperated，a structural equation model （SEM） is established to explore the impact of traffic and financial development on carbon emissions. Transportation and finance are placed in the same framework， and the mechanism and effect of the two factors on carbon emissions are analyzed in detail. Based on the relevant data from 2006 to 2016， the result shows that both traffic and financial development influence carbon emissions positively， but the impacts of each have a notable difference. Traffic development has significant impact on carbon emissions in direct and indirect paths， meanwhile， the direct effect outweighs indirect effect. There exist positive and negative functioning paths for financial development on carbon emissions， which makes the total effect small. In order to boost the development of the Belt and Road， it is suggested to improve green transport， green finance and green technologies.