Objective: To study the industrial circulating cooling water in different conductivity of metal corrosion of iron, and then take measures to prevent the pipe network system and equipment corrosion; methods: a rotating hanging plate method combined with electrochemical analysis theory, the relationship of circulating water test in different conductivity and iron corrosion rate; results: circulating water the conductivity in less than 2200 s/cm, the corrosion rate of iron is less than0.075 mm/a; conclusion: the concentration of sodium hydroxide 30% or 50% sulfuric acid to adjust the pH value of circulating water in 8.5-9.5, or add 2-10 ppm corrosion inhibitor and regular sewage and other measures of circulating water, can ensure the corrosion rate of metal iron is less than0.075 mm/a, meet the safety requirements of relevant standards within the range.