The corrosion mechanism of system of hydrogenation reactor effluent air collers was approached. By confecting simulation corrosion solution, it was researched the effect of experimental in various conditions on annual corrosion rate by means of the corrosion rate testing equipment of resistance probe and CMB-1510B portable instantaneous corrosion rate meterage. The investigated conditions included concentration of corrosion inhibitor, corrosion factor(Kp), pH value and synergistic effect. Results show that BTA corrosion inhibitor is an excellent inhibitor for system of hydrogenating reactor effluent air coolers, there exists good synergistic effect between (NaPO ₃)6 and ZnSO ₄ compounds in NH ₄Cl solution; at the same time, also indicate that annual corrosion rate rises obviously with the increase of corrosion factor, annual corrosion rate rises obviously with the decrease of it when pH value changes in lower range, effect of high pH value on annual corrosion rate lessens on the whole.