The study presents the results of ion exchange equilibrium carbonate treatment to prevent brass corrosion in open recirculating cooling water system. The treatment process can remove the hardness and aggressive anions, transform all of the ions into sodium bicarbonate and sodium carbonate, and form the open carbonate equilibrium system. In the static corrosion test, brass has the lowest corrosion rate of 1.36 x 10(-3) mm/year in the open carbonate equilibrium system with total alkalinity of 6.00 x 10(-3) And during the 8-day dynamic simulation experiment of ion exchange equilibrium carbonate treatment, the recirculating water with total alkalinity of 6.00 x 10(-3) mol/L that achieves open carbonate equilibrium state has the excellent buffer action when pH value of makeup water ranges from 5.94 to 11.26, and prevent brass after passivation with hydrogen peroxide (H2O2) solution from corrosion. So ion exchange equilibrium carbonate treatment is an effective and environmentally friendly method to treat the recirculating cooling water without corrosion inhibitor addition.