The product of Plastic coated pipe/Steel-plastic multiunit tubes is a modularized system consisting of pipe fitting and connecting fitting, wherein, the parts of the connecting fitting are formed by high-quality steels through pressing (it can be divided into various colors). After the surface of the high-quality steel tube is disposed, the outer surface of the wire is integrated by special thermoplastic conglutinant plastic layer, and the inner surface is covered with anti-rust layer, then the wire is produced, which has lots of advantages, such as beautiful outline, abrasion resistant.