A method of making a composite coating includes the steps of: adding a proper quantity of inorganic metal salt into an organic dissolvent to form a first mixed solution and then stirring the first mixed solution for 30-60 minutes; adding a proper quantity of SiO2 precursor into the first mixed solution to form a second mixed solution and then stirring the second mixed solution for 30-60 minutes; adding a proper quantity of catalyzer and water into the second mixed solution for being reacted with each other so as to form a coating solution via being stirred for 4-8 hours; and putting the coating solution under the room temperature for 24 hours so as to obtain the composite coating. A product formed with the foregoing composite coating includes a base body and a layer of composite protective film formed by the composite coating on surfaces of the base body.