The present invention relates to a composition for manufacturing insulation materials of an electrical wire and an electrical wire manufactured using the same. The composition for manufacturing insulation materials of an electrical wire according to the present invention includes 100 parts by weight of a base resin, made by blending 20 to 70 weight % of any one resin of an unsaturated organosilane grafted polyethylene and an unsaturated organosilane grafted ethylene alpha olefine copolymer, and 30 to 80 weight % of an unsaturated organosilane grafted ethylene copolymer; 10 to 25 parts by weight of a brominated flame retardant; 10 to 50 parts by weight of an inorganic flame retardant; and 0.2 to 5 parts by weight of compound, as a crosslink retardant, represented as a general formula of XnSi(OR)4-n (X is a phenyl group, R is a methyl group and n is an integer of 1 to 3).