Abstract: Through calculating the breathing loss of storage tank, the effectiveness of a new coating material CC-100 in energy saving was measured. Two 50000 m³ crude oil storage tanks with and without the coating material are selected as the reference object. Ambiant temperature and surrounding wind speed of the tanks and the average temperature of external surface of tank bodies as well as other parameters in the same day at four different time were tested. After light gas sampling, the component analysis was carried out using gas-liquid chromatography, and then calculating the breathing loss according to relevant standards. Result showed that for the tank with CC-100, the breathing loss decreased obviously, the light gas saved reached to 0.182 t/d. It is estimated that if the coating material is used, the initial investments will be recovered within 5 years.