To enhance the thermal properties of ultrahigh molecular weight (UHMW) (viscosity-average molecular weight of 6 x 10(6)) polyethylene (PE) gel film, this was crosslinked by dicumyl peroxide (DCP) during a high-temperature zone drawing, which is effective to orient film. Through a series of experiments, it turned out that crosslinking actualized by an optimum amount of DCP and high-temperature zone drawing technique caused significant changes in the structure and properties of UHMW PE gel film. That is, crosslinking increased storage modulus of UHMW PE gel film at 25 degrees C, resulting in improving thermal properties of the film. On the contrary, the crosslinking effect played a hindering role in raising the draw ratio of UHMW PE gel film. Maximum storage modulus of 165 GPa at 25 degrees C could be obtained at the draw ratio of 324 of uncrosslinked homo-PE gel film. In the case of crosslinked PE gel film, the highest storage modulus at 25 degrees C reached 65 GPa at maximum draw ratio of 150. Crosslinked film exhibited high modulus, even at 190 degrees C, to some extent, while uncrosslinked homo-PE gel film was molten completely at 150 degrees C.