NOVELTY - Malononitrile and lithium hydride are mixed in presence of specific solvent at preset temperature for 5 hours or more under inert atmosphere to obtain lithium-malononitrile solution. The lithium-malononitrile solution is purified, purified solution and perfluorosulfonyl fluoride resin having ethoxy groups in side chain are subjected to transformation reaction such that the solution contains excess lithium, to obtain perfluorosulfonyl bisnitrile amine lithium polymer electrolyte having bisnitrile amine-lithium groups in side chain.    USE - Preparation of perfluorosulfonyl bisnitrile amine lithium polymer electrolyte used for lithium-sulfur secondary battery (claimed).    ADVANTAGE - The lithium-sulfur secondary battery produced using perfluorosulfonyl bisnitrile amine lithium polymer electrolyte has high charge-discharge characteristics, cycle characteristics, and reduced loss of soluble active substances.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for lithium-sulfur secondary battery, which consists of lithium cathode, anode pole, electrolyte film and organic electrolyte. The electrolyte used for electrolyte film is perfluorosulfonyl bisnitrile amine lithium polymer electrolyte. The lithium cathode comprises lithium metal or lithium-containing alloy. The anode pole comprises conductive current collector and coating comprising positive electrode active material, electroconductive agent and binder coated on current collector. The positive electrode active material is elemental sulfur, organic sulfide, or carbon-sulfur polymer. The organic electrolyte comprises lithium salt and nonaqueous solvent. The lithium salt is chosen from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium trifluoromethylsulfonyl imide, lithium trifluoromethanesulfonate, lithium nitrate, and lithium polysulfide. The nonaqueous solvent is acetonitrile, cyclohexane, cyclohexanone, isopropanol, tetrahydrofuran, 2-methyltetrahydrofuran, ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, methyl formate, ethyl carboxylate, methyl acetate, ethyl acetate, propyl acetate, methyl propanoate, ethyl propanoate, ethyl butyrate, dimethoxyethane, 1,3-dioxolane, diglyme, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, sulfolane, dimethylene sulfone, or dimethyl sulfone.