China has large regional disparities in carbon dioxide CO2 emissions with economic development among its 31 provincial mainland regions. This paper investigates these disparities in CO2 emission patterns and identifies the factors underlying the differences. Results show that the 30 study China's mainland provinces (Tibet not included) can be divided into seven groups with three typical CO2 emission patterns. Index decomposition results indicate that changes in economic development, the industrial sector, and technology contribute far more to increased CO2 emissions than do population, energy structure, and other sectors. Close inspection reveals that different industry structures and technology contribute greatly to the differences observed in CO2 emissions between provinces with similar economic output. This study highlights the importance of region-specific industrial structure adjustment policies, especially for regions transitioning to heavy industry and for those still in the primary stages of industrialization. The potential application of a domestic carbon emissions trading system, to encourage regional investment in updated technology, is also discussed.