The invention relates to the field of power lithium ion batteries, in particular to a preparation method of a lithium ion power battery cathode. The preparation method comprises the following steps: first preparing sodium carboxymethylcellulose glue solution in a number 1 stirring machine, adding conducting carbon black and dry graphite powder in a number 2 stirring machine, uniformly mixing, and then adding the sodium carboxymethylcellulose glue solution in the number 1 stirring machine into the number 2 stirring machine; and adding little alcohol, vacuumizing, defoaming, adding styrene-butadiene latex, mixing, finally vacuum defoaming, and obtaining the lithium ion power battery cathode material. By improving a stirring scheme, the stirring time of the cathode slurry is shortened, the moisturizing coating performance of the cathode slurry is improved, and a bubble-free purpose is achieved.