The invention discloses a waterproof building-out cable which comprises a cable core and a sheath. The sheath is made from a modified fluororubber composite material. The modified fluororubber composite material comprises fluororubber, methyl vinyl silicone rubber, ethylene-propylene-diene monomer rubber, epichloro-hydrin rubber, an ethylene-vinyl acetate copolymer, fluororubber graft vinyl triethoxy silane, alumina, stearic acid, bisphenol AF, benzyl triphenyl phosphorus chloride, ethylidene thiourea, modified nano-silica, carbon black N550, silica powder, rectorite powder, talcum powder, calcined kaolin, barium sulfate, an accelerant PPD, an accelerant ZBPD, an accelerant CZ, dioctyl phthalate, epoxy fatty acid butyl ester, dibutyl sebacate, erbium oxide, lanthanum stearate, an anti-aging agent 2246 and 2,2'-ethylidene bis(4,6-di-tert-pentylphenol). The waterproof building-out cable is high in strength, good in water resistance and excellent in aging resistance.