The inhibition by 2-mercaptobenzoxazole (MBO) of copper corrosion in NaCl solution was investigated by means of potentiodynamic polarization, STM: QCM, XPS, FTIR and AES. The inhibition efficiency depended on MBO concentration, existence of NaCl and the immersion period of the copper sample. The inhibition efficiency of about 99% could be obtained by immersing for above 20 h in 3% NaCl + 1 mM MBO solution. The surface of the copper sample immersed in NaCl + MBO solution possessed FTIR characteristics different from those of MBO solution, irrespective of immersion time. The in-situ STM morphologies showed the rapid formation of a three-dimensional compact inhibition film on the surface of copper in MBO solution containing NaCl. XPS indicated that the inhibition film was cuprous and the chemical environments of S and N atoms were evidently changed. It is concluded that MBO reacted with the cuprous species from the corrosion process, and produced a water-insoluble cuprous complex to form the inhibition film and to retard the corrosion of copper.