Abstract: A synergistic effect of 1-hydroxybenzotriazole and sodium molybdate as corrosion inhibitors on copper in ASTM D 1384 simulated atmospheric corrosion solution was investigated by using electrochemistry, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Electrochemistry results revealed that BTAOH and Na₂MoO₄ compounding in 2 to 1, under the condition of a 50 mg×L^-1 concentration, could improve the charge transfer resistance and reduce the corrosion current density, and the inhibition rate significantly reached to 90.7%. Corrosion products of copper in this simulated atmospheric corrosion solution piled up on the copper surface in an accumulative column shape; but the copper surface was smooth and dense in the corrosion inhibitor containing media, the hydrophobicity enhanced, and the surface contact angle significantly increased to 91.8°. X-ray photoelectron spectroscopy (XPS) results showed that Na₂MoO₄ transformed into MoO₃ and MoO₂ after interaction with copper, and two kinds of oxides padded in the gap of a surface film formed by BTAOH, which increased the density of the film and had good protective effect on copper.