The invention provides a method of forming a coating film by forming in sequence a pigmented base coat and a clear top coat on a substrate followed by finishing by the two-coat one-bake technique, the method being characterized by using, as a coating composition for pigmented base coat formation, a composition comprising, as essential components thereof,(1) an OH-containing resin,(2) an amino resin,(3) a polyorganosiloxane(4) a flaky metal powder and/or a mica powder, and( 5 ) an organic solvent,and using, as a coating composition for clear top coat formation, a composition comprising, as essential components thereof,(1) an OH-containing base resin which further contains at least one group selected from the class consisting of a silanol group and a hydrolyzable group bound directly to a silicon atom,( 2 ) an amino resin, and( 3 ) an organic solvent.