The copolymer of the modified polyolefin with a polyamide (hereinafter often abbreviated merely to copolymer) can be easily obtained by melt-kneading the above-mentioned modified polyolefin and a polyamide such as nylon 6, nylon 12, nylon 66, etc. to thereby condense the carboxyl group of the modified polyolefin with the terminal amino group of the polyamide during the kneading process.