Energy-rich cities tend to rely on resource-based industries for economic growth, which leads to a great challenge for its low-carbon and sustainable economic development. The contiguous area of Shanxi and Shaanxi Provinces, and the Inner Mongolia Autonomous Region (SSIM) is one of the most important national energy bases in China. Its development pattern, dominated by the coal industry, has led to increasingly prominent structural problems along with difficult low-carbon transition. Taking energy-rich cities in the contiguous area of SSIM as examples, this study analyzes the main drivers of CO2 emissions and explores the role of economic structure transformation in carbon emission reduction during 2002–2012 based on structural decomposition analysis (SDA). The results show that CO2 emissions increase significantly with the coal industry expansion in energy-rich cities. Economic growth and structure are the main drivers of CO2 emission increments. An energy structure dominated by coal and improper product allocation structure can also cause CO2 emission increases. Energy consumption intensity is the main factor curbing CO2 emission growth in energy-rich cities. The decline of agriculture and services contributes to carbon emission reduction, while the expansion of mining and primary energy processing industries has far greater effects on CO2 emission growth. Finally, we propose that energy-rich cities must make more efforts to transform energy-driven economic growth patterns, cultivate new pillar industries by developing high-end manufacturing, improve energy efficiency through more investment in key technologies and the market-oriented reform of energy pricing and develop natural gas and renewable energy to accelerate low-carbon transition.