Abstract: The situation and tendency of building energy consumption and the destructive effect on air environment due to this building energy consumption are introduced. If afforestation on the building roof had been widespread, building energy consumption( especially in summer) and the destructive effect on air environment due to this building energy consumption could be greatly lowered, also the capacity of air conditioning services, the operational time and intensity of air conditioning system, the environmental load from the air conditioning services and system could also be lowered, our air environment could be better upgraded.