Abstract: This study calculates the provincial carbon emission efficiency along the Belt and Road in China from 2013 to 2017 based on the Super-SBM-undesirable model, the spatial Dubin model is used to investigate the spatial influencing factors and spillover effects of provincial carbon emission efficiency along the line. Our results show that: (1)The carbon emission efficiency of provinces along the line is low and shows obvious geographical differences. (2)The carbon emission efficiency of provinces along the line shows a non significant positive correlation with the technical level, while the economic growth, energy structure and industrial structure show a significant negative correlation. (3)By decomposing the total effects, we find that the positive spatial diffusion effects of carbon emission efficiency of provinces along the line come from technical level factors, and the spillover effects of economic growth, industrial structure and energy consumption are the main reasons for the decline of carbon emission efficiency in adjacent areas.