The invention discloses a lithium ion power battery and a preparation method thereof. According to the invention, the cathode pole piece of the lithium ion power battery comprises, on a mass percentage basis, 83 to 94% of lithium titanate, 2 to 10% of an adhesive and 3 to 10% of a conductive agent; the anode material of the lithium ion power battery comprises, on a mass percentage basis, 83 to 95% of nickel-cobalt-lithium manganese, 1 to 10% of an adhesive and 4 to 12% of a conductive agent. Lithium titanate (Li4Ti5O12) is used as an active substance of the cathode of the lithium ion power battery in the invention, and nickel-cobalt-lithium manganese is used as an active substance of the anode; the lithium ion power battery has the advantages of great capacity, an excellent charge-discharge rate, a long cycle life and high volumetric specific energy; the preparation method provided in the invention has the advantages of low cost and a simple and practicable process.