The invention relates to a nickel-cobalt-aluminum ternary cathode material with high tap-density and a preparation method of the nickel-cobalt-aluminum ternary cathode material. The method comprises the following steps: adding a nickel-cobalt mixed solution, a precipitant solution and a complexing agent solution to a reaction kettle in parallel flow; controlling the pH value, the temperature, the complexing agent concentration and the stirring speed in the reaction kettle, carrying out co-precipitation reaction and overflow discharge, washing slurry until the pH is smaller than 8.0, and carrying out drying and sieving to obtain spherical nickel-cobalt precursor powder; and mixing the nickel-cobalt precursor powder, an aluminum-containing compound, a doped compound and a lithium salt evenly, presintering the mixture at a low temperature, directly increasing the temperature for heat preservation, naturally cooling the mixture, and crushing an sieving the mixture to obtain the nickel-cobalt-aluminum ternary cathode material with high tap-density. Divalent metal ions are doped, so that a layered crystal structure of the material is stabilized; the content of Ni<3+> is improved; and shuffling of Li<+> and Ni<2+> ions is reduced. According to the method, continuous mass production can be achieved. The nickel-cobalt-aluminum ternary cathode material has the advantages of good rate capability, high discharge capacity, long cycle lifetime and the like.