Abstract: In order to employ the high-efficiency, low-power-consumption ultraviolet light technology for the cross-linking of the ethylene propylene diene monomer (EPDM) rubber cable insulation layer and achieve the goal of energy conservation, pollution reduction and efficient production, it is necessary to develop EPDM insulation formulation with low content of solid fillers. In this paper, EPDM was reinforced by adding linear low density polyethylene (LLDPE) and a small amount of nano SiO₂. The formula of photo crosslinkable EPDM insulating material was designed, and the mechanical, crosslinking and electrical properties of UV crosslinked EPDM were systematically studied. The results show that, with the irradiation time increasing, the mechanical properties of EPDM are significantly decreased, and the crosslinking degree is rapidly increased. Compared with EPDM, the crosslinking degree and mechanical properties of LLDPE/EPDM materials are significantly higher. When the LLDPE content is 10wt%, the elongation at break of the LLDPE/EPDM material is 539%, the tensile strength is 12 MPa, and the Shore hardness is 80 A, which can meet the requirements of use. For SiO₂/EPDM composite, when the SiO₂ content is 4% (mass ratio to rubber), the mechanical properties are the best, the elongation at break is 596% and the tensile strength is 14 MPa. Compared with EPDM, the hardness of SiO₂/EPDM composite is almost unchanged, but the crosslinking degree is reduced. When the irradiation time is 12 s, the loading elongation of SiO₂/EPDM is 40%, which still meets the requirements of use. The degradation of the material during irradiation can be suppressed after 0.5% mass ratio of Irganox1010 is added, and the mechanical properties of the composite material are improved. Moreover, Irganox1010 can improve the thermo-oxidative aging resistance of the composite. Both two kinds of modified EPDM composites which are designed for UV cross-linking technology can meet the requirements of cable insulation. The blending of LLDPE increases the crosslinking degree and electrical properties of the material, but bring the negative impact on the hardness of EPAM, while the doping of SiO₂ has almost no effect on the hardness of the composite, but the crosslinking degree and electrical properties are slightly weakened.