The main reason of energy demand growth in China from the perspective of life cyce of society was analyzed. After that, the basic concept of energy saving for China was analyzed, and the importantce to distinguish the construction energy consumption and the operation energy consumption were pointed out. Then, the strategic goal of mid-long term energy saving of China, and three ways to implement it were proposed and they were: institutional energy saving, systematic energy saving and technological energy saving. And a case study of systematic energy saving for the problem of the life time of domestic building was also introduced.