The invention discloses a preparation method of a LiFePO material, a lithium ion battery using the material and a positive plate thereof. The preparation method comprises the following steps: sintering to prepare LiFePO powder; cladding aluminum on the surface of the LiFePO powder particle to form a LiFePO-Al composite material. Compared with the prior art, the LiFePO material prepared by the invention and the cladding aluminum can carry out homodisperse and surface cladding at the molecule level; the conductivity of the electrode plate prepared by the invention is improved by 101-10001 times; and the internal resistance of the LiFePO lithium ion battery is reduced greatly, and the large-current charge-discharge property is obviously improved, thus the material is particularly suitable for a high power lithium ion battery. Compared with the other cladding elementary metal, Al metal is cheaper, has lighter mass, lower melting point, more stable electrochemistry property and the like; and in additional, the aluminum in the composite material and a positive pole current collector are made of the same material, so that primary battery corrosion effect can not be formed.