Abstract: Based on an analysis of the variation of China’s electricity elasticity coefficient since 1978, this paper elaborates the reasons for the large variation of China’s electricity elasticity coefficient in the short term, and finds out the long-term pattern of the variation. Through comparison with the developed countries’ experience in electricity elasticity coefficient variation, a method is proposed for the application of electricity elasticity coefficient during economic transition period, and a check is made on the power demand forecasting for the 13th, 14th and 15th Five-Year Periods (2016–2020, 2021–2025 and 2026–2030, respectively).