Urbanization and rapid economic growth make Beijing shoulder heavy responsibilities in carbon emission reduction. Through calculating the total carbon emission in Beijing, summarizing the characteristic of carbon emission and utilizing LMDI decomposition method to analyze the increment of carbon emission in Beijing, the result shows that the growth of per capita economic aggregate is the most important factor for the high-speed growth of carbon emission in Beijing and the improvement of energy utilization efficiency is the main reason to curb carbon emission growth. Under the overall environment of rapid economic growth, adjusting industrial structure, improving energy utilization efficiency, optimizing energy structure and relying on technical innovation and institutional innovation is the basic solution to achieve the target of emission reduction.