Based on the corrosion issue of cooling water system containing carbon steel and copper alloy, the corrosion behavior of SA 106GrB steel and brass was studied using potentialdynamic polarization, electrochemical impedance spectroscopy (EIS) and immersion methods in solution containing NaNO2, Na2MoO4 and TTA-Na at 35 ℃.The results show a synergistic effect between Na2MoO4 and NaNO2 acting as passivating anodic corrosion inhibitors on SA106GrB steel, of which inhibition efficiency (IE) could reach 98.4% in pH10 solution with an optimal compound by a concentration ratio of 3.2∶1 (as ppm MoO42-∶ ppm NO2-) while this compound have little benefit on corrosion inhibition of brass without TTA.When TTA-Na was added into the solution, the chemisorption between TTA molecules and brass surface could increase the inhibition for both anodic and cathodic reactions and the IE could reach 99.5% in pH10 solution with an optimal compound by a concentration ratio of 3.2∶ 1∶0.7 (as ppm MoO42-∶ ppm NO2-∶ ppm TTA).The influence of C1-on the corrosion inhibition (especially on pitting) was also studied in 10 ppm CI-solution containing compound inhibitors.The results show that Na2MoO4+ NaNO2 could raise the breakdown potential from-581 mVscE to 747 mVscE thus effectively inhibit pitting by competitive adsorption with C1-.But the addition of TTA-Na seems to have a negative effect on corrosion current density and impedance probably because TTA covering layer might impede the inflow of anions such as C1-or MoO42-/NO2-so that MoO42-or NO2-could not react with metals adequately.For brass, the breakdown potential moved from 0.0 mVscE to 1208 mVscE but no remarkable benefit on IE increasing was observed as reported in literatures that halide ions may facilitate adsorption of organic inhibitors.The reason may be due to the competitive adsorption between C1-and MoO42-/NO2-.