The invention discloses an anode material trihalide polymer for lithium battery and the preparation method for lithium battery. Carrying out oxidative polymerization with thiofuran derivatives such as thiofuran, alkoxy thiofuran, alkyl thiofuran, hydro sulfo-thiofuran, 3, 4- sulfo thiofuran to produce poly thiofuran, poly alkoxy thiofuran, poly alkyl thiofuran, poly hydro sulfo-thiofuran, poly 3, 4- sulfo thiofuran; preparing anode with thiofuran polymer, carbon black and politef, and assembling lithium secondary battery by taking (CxF2x+1SO2)2NLi, CxF2x+1SO3Li, (CxF2x+1SO2)(CyF2y+1)NLi as electrolyte, employing dioxohexacyclic ring, dioxolane and glycol dimethyl ether as solvent, and taking metal lithium slice as negative pole. The discharge specific capacity of assembled lithium secondary battery is 400 Ah/ kg to 1200 Ah/ kg, and the cycling stability is sound.