First, this paper adopts the SBM-Malmquist model, which includes undesired output indicators, to examine the carbon emission efficiency of 11 provinces and municipalities in the Yangtze River Economic Belt from 2004 to 2021 in both a static and dynamic way. Subsequently, this paper utilizes the Tobit regression model to investigate the variables that impact carbon emission efficiency. The empirical results indicate that: (1) Although the data indicates a gradual rise in the carbon emission efficiency of the provinces and municipalities within the Yangtze River Economic Belt, the total level of carbon emission efficiency remains relatively low. (2) Urbanization level and technological progress contribute significantly to carbon efficiency, while two factors, the opening-up level and energy structure, reduce it.