Abstract: The paper consists of three parts:1) the discipline structure—population energ etics and ecological energetics;2) development history and the present status in China;3) the scope of population energetics.The third part emphasizes estima ting the energy demands of a population involving integrating individual energy demands with information on population size,structure,and dynamics.It include s individual metabolism,energetic equivalence of different activities,breeding energy and daily energy expenditure (DEE) and so on.