The present paper analyzes historically the relationship between carbon emission and economic development by differ- ent stages through adopting elastic decoupling methods and Tapio evaluation criteria along with a comparison with the national Five Year Plans. The analysis shows that the influencing factors to the relationship between carbon emission and economy in China are different, and economic development and carbon emission have less connection in the recent 30 years of reform and opening-up in China. It is a difficult task to realize the promise that we will reduce carbon emission by 40%-50% in 2020 based on the data from historical experience and different expectations for economic development from economists. Through constructing the calcula- tion model of carbon emission intensity gap according to different development scenarios, the analysis shows that economic growth, infrastructure investment and further development of industrial- ization are the main drivers to the increase of carbon emission, technological progress, and particularly, the reduction of energy consumption is the primary means to reduce carbon emission in China. It is imperative to transform the economic growth pattern, and it is a grand task to perform and there is a long way to go for China to maintain economic growth and reduce carbon intensity.