The carbon emissions from a specific sector may be large, but it may be the results driven by other sectors as the production of this sector is heavily demanded by other sectors. On the other hand, the emissions from a sector may be small, but this sector can drive other sectors to release carbon emissions as this sector consumes products made by other sectors. Therefore, this research examines the key emission sectors in China from a driving-driven perspective. By referring to Input-Output Table and China Energy Statistical Yearbook in the year of 2012, 31 emission sectors are mapped out and key emission sectors are identified. The driving-dominant sector is sector 13 (Nonmetal mineral products). Driven-dominant sectors are sector 3 (Petroleum and natural gas extraction), sector 29 (Wholesale, retail trade, lodging and catering services), and sector 31 (Others). The driving-driven sectors are sector 2 (Coal mining and dressing), sector 11 (Petroleum processing and coking), sector 12 (Chemical products), sector 14 (Smelting and pressing of metals), sector 25 (Electric power, steam and hot water production and supply), and sector 30 (Transportation, storage, postal and telecommunications services). The finds provide important reference for governments to adopt effective carbon reduction measures addressing the key emission sector to achieve the largest extent carbon reduction.