Abstract: Value engineering is a kind of soft science developed from how to make full use of the resources,and it is an effective way to advance the value of products.It is analysed that the necessity,feasibility and rationality of adapting VE principles to the design of energy conservation in building.It is also illustrated the dialectical relationship among the investment on energy conservation in building,the expenses of making use of it and its life cycle cost.Comparing the value of space enclosing structure of common building with that of energy conservation in building(F/C) by analyzing some cases,it is finally put forward some effective ways to implement energy conservation in building, so as to apply VE principle to design energy conservation in building.