Specific embodiments of the present disclosure provide a composite coating. In the composite coating, a plasma of a multifunctional-group monomer having an epoxy structure and a plasma of an ester-based coupling agent are used to form a coating as a base coating, and a plasma of an unsaturated ester-based monomer having aromatic ring(s) and a plasma of an ester-based coupling agent are used to form a coating as an anti-corrosion coating. The composite coating has a high binding force with a substrate and a strong corrosion resistance.