As the fast development of economy and city construction, the air-conditioning system is necessary for the public building such as commercial building, office building, hotel etc. Energy consumed by air-conditioning system accounts a big percentage of the total energy amount consumed in the building. So does the cold and heat sources. If the energy efficiency of the cold and hot sources is improved, the energy efficiency of the building should be improved, which is an important way for building energy conservation. In the paper, some site tests have been processed with cold and heat sources in air-conditioning systems in some public buildings. The energy efficiency of performance (EER) of the cold and heat sources is analyzed. The EER of some cold and heat sources is relatively low, which may be caused by the air-conditioning system itself, or by the cold and heat source’s automation control or by the operation management and so on. Also the paper pays more attention to the improvement of the energy efficiency of performance of the cold and heat sources in some buildings. It is believed that the paper is useful to improve the building energy efficiency.