Abstract: The effect of radiation cross-linking doses on PTC （positive temperature coefficient） characteristic and heating performance of LLDPE/EVA/CB composites were investigated. The rela- tion between structure and property of the LLDPE/EVA/CB composites was analyzed by using DSC （differential scanning calorimetry）, DMA（dynamic mechanical analysis）, SEM（scanning electron macroscopy）, TGA （thermogravimetric analysis） and TEM （transmission electron macroscopy）. The results show that the interfaces between LLDPE , EVA , and carbon black particles can be remarkably improved. A negative temperature coefficient （NTC） phenomenon can be eliminated and the heating stability of the element made from LLDPE/EVA /CB composite can be enhanced .