Energy is the most basic driving force for socio-economic development, and the basis for human survival. With the rapid economic development, energy scarcity has gradually been appeared. Moreover, low energy efficiency is the prominent problem in China. In this paper, the energy intensity of Guangdong, Hunan and Guizhou were analyzed based on Laspeyres decomposition method. We found that: 1)The difference of energy intensity are large obviously among the three provinces, particularly in Guangdong and Guizhou. Nevertheless, the differences of energy intensity will gradually become smaller among the three provinces in the future. 2)The structure share and efficiency share of primary industry are beneficial to reduce energy intensity. The structure share of secondary industry can increase the energy intensity, but the efficiency share of secondary industry can reduce energy intensity. Moreover, the efficiency share of secondary industry plays an strongly import role in reducing energy intensity. The structure share in Guangdong Province is negative. But they are positive in Hunan and Guizhou. The efficiency share of tertiary industry of Guangdong and Hunan is negative or positive during different periods. The reasons need further study. Whereas, the efficiency share of the tertiary industry is negative in Guizhou. 3) The structure share in three provinces is negative to energy intensity. The efficiency share of the three provinces can reduce energy intensity, the roles vary from region to region. In this paper, we suggest the great effort should focus on economic underdevelopment or high energy intensity areas in order to reduce energy consumption by 20% of unit of GDP in the near future and guarantee energy security.