The invention relates to a preparation method of a nickel-cobalt-manganese precursor, which specifically includes the following steps: preparing nickel-cobalt solution, nickel-manganese solution and nickel-T solution by mixing soluble nickel salt with soluble cobalt salt, soluble manganese salt and soluble salt doped with metal T respectively, wherein the concentration of the nickel-cobalt solution is higher than that of the nickel-manganese solution, and the concentration of the nickel-manganese solution is higher than that of the nickel-T solution; mixing the nickel-cobalt solution with thenickel-manganese solution and adding a complexing agent to obtain a mixed solution, and adjusting the pH value of the mixed solution to 9-11.5 by adding alkali solution; and adding the nickel-T solution to the mixed solution for reaction in an inert atmosphere to obtain nickel-cobalt-manganese precursor particles with uniform size, high purity and stable chemical performance. The prepared nickel-cobalt-manganese precursor particles show a gradient decrease in the relative content of nickel element and a gradient increase in the relative content of doped element from the core to the surface.