The work aims to prepare amorphous structured color coatings based on SiO2@CA microspheres and get the method of regulating the structured color as a potential application of functional packaging or smart packaging. Caffeic acid (CA) and SiO2 microspheres were catalyzed by CuCl2 and NaBO3-4H2O to generate reactive oxygen species (ROS), which rapidly oxidized CA to strongly adherent polycaffeic acid (PCA) coated SiO2 microspheres, thereby preparing SiO2@CA composite microspheres, and the suspension composed of the composite microspheres and anhydrous ethanol was sprayed on the surface of hydrophilized glass substrates to obtain amorphous structured color coating layer. The SiO2@CA composite microspheres and their structured color coatings were characterized by FT-IR, XPS, TGA and SEM, and the effects of CA content, mass ratio of CuCl2/CA and mass ratio of NaBO3-4H2O/CA on the morphology of the composite microspheres and the optical properties of the structured color coatings were investigated. Suitable SiO2@CA composite microspheres and structured color coatings could be obtained under the preparation conditions of 5% CA, mass ratio of CuCl2/CA as 1∶2 and mass ratio of NaBO3.4H2O/CA of 6∶4. CA could effectively improve the color contrast of the amorphous structured color coating and realize the color regulation.