Abstract: The study on the regional carbon emission differences is important to the reasonable allocation of the regional carbon emission reduction task and the smooth realization of the carbon emission reduction targets. The paper is based on the Theil index, which systematically analyzes the regional carbon emission distribution characteristics and differences, exploring the cause and effect of the carbon efficiency of the eastern, central and western regions. The results show that: China carbon emission efficiency is not evenly distributed in space; the per unit GDP carbon emission and per capita carbon emission have significant differences; the western area is the main region that contributes to the high national average carbon intensity which means it’s crucial to realize the western carbon emission targets. According to study above, the paper provides recommendations for reasonable carbon emission reduction task allocation and effective economic policies.