It was introduced that the liquid phase fusion mixing and reaction mechanism of preformed polyether-type polyurethane and modifying agent of vinyl chloride-vinyl acetate copolymers [P(VC-VAc)]. The effects of P(VC-VAc) quantities, fusion temperature and mixing time on properties of composite material were studied. The composite material and aggregate construction were characterized by FT-IR and X-ray diffraction. The results show that surface resistivity coefficient can surpass 1015Ω, the volume resistivity coefficient can be over 1014Ω·cm. Besides of excellent eletroinsulating properties, this composite material also has other fine features, such as high hardness and elasticity, convenient form of construction work, resists wearing and flexure, and so on. As a result of these outstanding performances, it can be applied broadly to the quick renovation of cable, potting of cable joint, electronic component and printed circuit, and electric engineering materials.