NOVELTY - A lithium ion battery anode material comprises lithium iron phosphate in form of nanometer fiber having smooth surface, a diameter of 170-250 nm; length of more than 100 microns, and olivine type structure.    USE - As lithium ion battery anode material (claimed) used in a fuel cell.    ADVANTAGE - The fiber has smooth surface, diameter of 170-250 nm and length of more than 100 microns. The anode material of the lithium ion battery has magnifying power of 0.1C, has first discharge specific capacity of more than 160 mAh/g, does not reduce after circulating for 20 times, and has resistance of less than 120 ohm.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparing lithium iron phosphate nanometer fiber involving: a) preparing the spinning solution comprising the lithium source, iron source, phosphorus source in a solvent, stirring it to obtain lithium iron phosphate precursor solution, where the lithium iron phosphate precursor contains at least one of lithium source, iron source, phosphor source, and the lithium source is a mixture of nitrate and/or lithium hydroxide, the iron source is mixture of nitrate, acetate, chloride, iron dichloride or ferrous sulfate, the phosphorus is mixture of phosphoric acid, diammonium hydrogen phosphate, ammonium dihydrogen phosphate or ammonium phosphate, where the solvent is water, ethanol or N,N-dimethyl formamide (DMF), and the lithium source, iron source and phosphorus source are counted by the proportion 1:1:1 according to the amount of substance; adding macromolecule template to the lithium iron phosphate precursor solution; stirring it to obtain the mixed spinning solution of the lithium iron phosphate precursor and macromolecule, where the macromolecule template agent is polyvinylpyrrolidone (PVP) or polyvinyl alcohol (PVA), having proportion (mass percent) of: lithium iron phosphate precursor (8-25%), or solvent (10-25%); preparing lithium iron phosphate precursor/polymer composite nano fiber by electrostatic spinning method, where the spinning voltage is 8-25 kV, solidifying distance is 10-25 cm, the spinning temperature is 10-30 degrees C, the humidity is 30-60 degrees C; where the lithium iron phosphate precursor/polymer composite is prepared at a heating rate of 0.5-10 degrees C/minute, first insulating at 4 degrees of 300-400 degrees C air for 8 hours, then at 600-800 degrees C under the nitrogen or argon gas atmosphere at retained temperature of 10 degrees C; and then naturally cooling to room temperature to obtain the lithium iron phosphate nano fiber.