In this study, benzotriazole (BTA) used as a good inhibitor on corrosion of copper in 3.5% NaCl or 0.001 M HCl has been studied through immersion tests. It was found that at the concentration of 4% BTA, the inhibition of corruption of copper by forming a couprous ion- BTA condensation compound in minium 24 hours exposure. The increasing of concentration of NaCl or HCl concentration will increase the corrosion of coper but can be controlled by BTA film. Key words: benzotriazole, corrosion of copper, sodium chloride