This paper introduced the rationale of applying input output method and scenario analysis to project energy requirements and energy intensity; and set up the general framework of a model for scenario analysis of energy requirements and energy intensity, based on input output method. According to the model, a set of scenarios were developed by introducing step by step the major impact factor of energy requirements in China's economy and society; the energy requirements and energy intensity of year 2010 and year 2020 were projected, using the data of year 1997; the impact of the perceived changes in the economy and society on energy requirements and energy intensity were quantitatively analyzed; some related conclusions were attained and some corresponding policy suggestions were proposed.