For the further study on corrosion behavior of offshore concrete structure and sacrificial anode cathodic protection, a field experiment was carried out on a reinforced concrete column near northern trestle of Qingdao Bay Brigde, and ECI monitoring instrument was used to measure the corrosion condition. Results based on 9000 hours field experiments showed that the use of sacrificial anodes could be an effective means for the protection of offshore concrete structure. Meanwhile, ECI monitoring instrument could be applied in practical project due to its effective and accurate working.