Abstract As an environment-protecting water-borne coating,the cathodic electrophoretic coating has wide application prospects.The cathodic electrophoretic coating of epoxy resin was prepared with half blocked isocyanate as curing agent.Reaction condition of the synthesis of resin was investigated,and properties of the obtained electrophoretic coating were tested.The results show that the coating film with flat,smooth and excellent performance can be obtained under the condition of appropriate electrophoretic parameters.