The coating film formed on an automobile body has softness during a film formation even on a thermally expandable/shrinkable base, and the cured film has an excellent appearance.Provided is a method for forming a multilayer coating film, the method comprises: applying an aqueous intermediate coating composition and preheating the applied composition at 60 to 90° C. to form an uncured film;preheating to form an uncured base coating film and a clear coating film; and baking and curing these uncured films to form a multilayer coating film, wherein the aqueous intermediate coating composition comprises (a) an acrylic resin emulsion having a specific properties, and (b) a film formation auxiliary agent that is a fatty acid diester compound having a boiling point of 280° C. to 350° C., and a cured film comprising (a) and (b) at a mass ratio of 3:1 has a rupture elongation of 1% or more.