A method for producing a coating layer with scratch resistance and flex resistance, a laminated structure, and a coating composition are provided. The method includes coating the coating composition on a plastic substrate and performing a curing operation on the coating composition to form a cured coating layer. The coating composition includes a polyhedral oligomeric silsesquioxane, a multifunctional epoxy resin, a cationic light initiator, and an organic solvent, and the polyhedral oligomeric silsesquioxane has a cage-like structure. The curing operation has a baking temperature that is within a range from 75° C. to 200° C., a baking time that is within a range from 30 s to 120 s, and an UV curing energy that is within a range from 250 mJ/cm2 to 1,250 mJ/cm2.