Abstract: The scaling and corrosion is a common phenomenon in the circulating cooling water system． The method to solve the issue is to add the scaling and corrosion inhibitor． Ozone ( O3 ) processing method can achieve corrosion and scale inhibitor、 disinfection and other multi-function． The paper discussed ozone processing used in warm-water circulation system，and studied the scale and corrosion situation under different quantity of ozone to determine the optimal dosing quantity． The result showed that: When ozone optimum dosage was 4. 5 mg /L，20 carbon steel and cast iron had the best corrosion ability． The lowest corrosion rate of 20 carbon steel was 0. 228 mm/a，reducing 75% compared with the blank test; the cast iron was 0. 282 mm/a，reducing 61. 5% compared with the blank control group． When ozone dosing quantity was 9. 0 mg /L，the corrosion rate of galvanized was 0. 206 to 0. 275 mm/a，going down of 38. 2% compared with the blank control group． The corrosion effect was obvious．