Measuring and analysing carbon leakage are the foundation for improving environmental responsibility. Based on the origin–destination approach and spatial spillover analysis, this study explores factors of China's inter-provincial carbon leakage. A multiregional input–output model was used to obtain the carbon footprint of consumption, and the factors of carbon leakage were assessed. The results revealed that the economic development and environmental regulations of the origin and destination have opposite effects on carbon leakage. Accordingly, provinces with high-energy intensity and abundant energy resources are mainly net-exported carbon, whereas provinces with underdeveloped secondary industries are mainly net-imported carbon. Notably, a positive spillover effect of energy intensity exists at the origin, and a negative one occurs at the destination. Moreover, a positive spillover affects the origin's energy output, and the surrounding areas' energy endowment can create favourable conditions for carbon leakage at the origin. Finally, corresponding policy suggestions are presented based on the above analysis.