Complete set of water treatment technology of offshore oilfield was developed to solve the produced water of Liuhua Oilfield, and this technology was applied successfully in Liuhua Oilfield. Research and practice indicated that the technology could inhibit effectively the complicated corrosion caused by H2S,CO2,SRB and solved salts in offshore oilfield. The technology could also reduce the discharge of waste oil, save the cost of run, and insure the treatment of oilfield produced water meeting the environment standard and the long period of safe operation.