Under the background of China-style decentralization, due to easing self financial pressure and political promotion, the investment behaviors of local governments can directly or indirectly affect regional electric power demand. The system GMM is used to estimate and analyze dynamic panel system of 30 provinces and municipalities during 1999—2010, the analysis results coincide with theoretical forecast. The results are that financial decentralization, electric demand and marketization can boost economic growth, that the economic growth, secondary industry proportion, marketization degree and urbanization level of different provinces and municipalities can significantly influence the demand for electric power, that financial decentralization, population and electric power consumption index are positively related to electric power demand, however, price is negatively related to electric power demand, and that the same influential factor has different actions on electric power demand in different provinces and municipalities.