The control conditions of indoor thermal environment given in " Thermal design code for civil building"(GB-50176-93) have great significance to determining the design standard for energy efficiency of enclosure for buildings.In this paper,on the basis of "Thermal design code for civil building",from viewpoint of system engineering,the enclosure of building is accounted as a thermal boundary surface system separating the atmosphere into indoor and outdoor spaces with the properties of heat insulation and heat preservation.The controlling method related to the design standard in thermal environment and energy efficiency in buildings is perfectly put forward with the idea of inheritance,development and innovation.