A numerical simulation method of chloride ion induced corrosion was proposed. Based on the different corrosion mechanisms of submersion zone, tidal zone, splash zone and atmosphere zone, a series of theoretical equations were built by taking into account the effect of temperature, humidity, concrete age, chloride ion concentration and seawater convection etc. Further,a numerical simulation ... [Show full abstract] program was developed to simulate the service status of a bridge pier of Qingdao bay bridge by means of COMSOL coupled with factors such as temperature, humidity and chloride ion transmission etc. The results show that: (1) the numerical method can simulate chloride ion induced corrosion well; (2) the place where depassivation occurred for the reinforced steel bar corresponds to submersion zone, tidal zone, tidal zone and atmosphere zone in turn; (3) for this living example, the first depassivation of reinforced steel bars for a bare reinforced concrete bridge pier may occur in the place about -2.200 m (near to the center of tidal range zone) after in service for 25 a. © 2015, Chinese Society of Corrosion and Protection. All rights reserved.