The present invention relates to a polyamide/polyphenylene ether resin composition containing: a base resin comprising polyphenylene ether, a polyamide and an impact modifier; a compatibilizer; and a polyamine, and to: a polyamide/polyphenylene ether resin composition having a notched Izod impact strength of about 12 kJ/m2 or more when measured at 23° C. according to the ISO 180 standard, and a number of checkerboard lattices, in which peeling off occurs, being about 5% or less of the total number of checkerboard lattices in a 1 mm-gap checkerboard pattern test for testing adhesion to acrylic paints and melamine-based paints according to the JIS K5600-5-6 standard; and a preparation method therefor.