Abstract: Filler is used in the processing of wire and cable of PVC to improve itsmechanical and electric properties, but in the process of irradiation crosslinkingof wire and cable of PVC, the experimental. results show that filler not onlyimproves properties of XLPVC, and its effect of radiati on crosslinking is obvious,too. Therefore, in this paper, the effect of different fillers on thermal stability,mechanical and electric properties is investigated and the sensitization of fillers iscompared each other from following equationR(S+1/2S)=B+AR~βand R_(gel)(gel point dose). The XLPVC sample which uses kaolin as filler has betterelectric properties and the XLPVC samples which use TiO_2 or CaCO_3 have bettermechanical properties.