Electrochemically anticorrosive behaviors of 4-methyl-4H-1,2,4-triazole-3-thiol (4-MTTL) monolayers self-assembled on copper surface have been investigated by electrochemical impedance spectroscopy (EIS), electrochemical polarization measurement and surface-enhanced Raman scattering (SERS) spectroscopy. The EIS mechanism of the copper surface adsorbed with 4-MTTL monolayers was fitted with the mode of R(QR)(QR)(CR). The electrochemical polarization experimental results indicated the high inhibitive efficiency of about 81.1%. Potential dependent SERS result suggests that 4-MTTL molecule was anchored at the copper surface via S-6 and N-2 atoms with a tilted orientation, which resulting in a strong interaction between the 4-MTTL molecule and copper surface. The molecule tended to experience a transition state of the adsorption at the copper surface via S-6 atom only as the potential applied at -0.5 V vs. SCE. (C) 2011 Elsevier B.V. All rights reserved.