Objective To compare the inhibition performance of two corrosion inhibitors: 1, 2, 4-triazole and benzotriazole, in order to explore their adsorption types on Cu surface and explain the inhibition mechanism from experiment and molecular simulation point of view. Methods Potentiodynamic polarization measurement was used to test the corrosion inhibitive efficiency of the two inhibitors. The adsorption isothermal fitting method was used to explore their adsorption types on Cu surface. Adsorption energy, deformation charge density and partial density of states were calculated using quantum chemistry calculation method to explain their inhibition mechanism. Results The results of polarization measurement showed that the inhibition efficiency of benzotriazole was higher than that of triazole at all concentrations. The relationship of concentration and coverage of the two inhibitors accorded with the Langmuir adsorption isotherm, and their adsorption free energy was in range of -35 ~ -37 kJ / mol. The absolute value of adsorption energy of benzotriazole (top -4. 41eV, bridge -4. 36 eV) was larger than that of triazole (3. 28 eV). Obvious charge transfer occurred in the adsorption process, and the electron atmosphere distributed between the two bonding atoms. In addition, the s,p orbits of N atoms and the d orbit of Cu atoms overlapped during the adsorption process. Both of the neutral and protonated forms of the two inhibitors could parallelly adsorb onto Cu surface. Conclusion The inhibition performance of benzotriazole was better than that of triazole, which was due to the higher adsorptivity of benzotriazole compared to that of triazole. Both chemical adsorption and physical adsorption existed in the interaction of the inhibitors and the Cu surface, and the chemical adsorption of inhibitors on Cu surface was attributed to the covalent bond between N and Cu atoms, and the bonding interaction was due to atomic orbits hybridization, while the physical adsorption between the inhibitor and Cu surface consisted of both Van der Waals forces and electrostatic attraction.