Abstract: The perforation leakage happened to the inner evaporator long U-shaped copper tubes of an air-conditioner used in a hair salon after a few months of installation. Macroscopic examination, metallographic analysis, corrosion product composition analysis and reappearance test were conducted on the copper tube to find out the causes of its corrosion leakage. The results show that the substances volatilizing from the hair sprays, hair dyes, baking ointment and other products used in the hair salon gathered on the surface of the copper tube in the wet environment and formed carboxylic acid ions such as formic acid and acetic acid which easily caused nest corrosion and chloride ions which easily caused pitting corrosion, which resulted in the perforation leakage failure of the copper tube. Accordingly, it was recommended to develop corresponding more corrosion-resistant air conditioning models.