A method of forming a heat-resistant product, produced from a polymer composition comprising 40-70 weight % of a thermoplastic elastomer containing a repeating unit derived from ethylene and a repeating unit derived from propylene and 60-30 weight % of an ethylene-vinyl acetate copolymer containing 7.5 weight % or more of a vinyl acetate repeating unit, which comprises blending the polymer composition at a temperature of 160.degree. C. or less, molding it at a temperature of 180.degree. C. or less, and then cross-linking the resulting molded product by irradiating it with an electron beam or by heating to produce a foamed product which has good shape memory characteristics.