The invention relates to a preparation method of a continuous nickel-cobalt-manganese ternary precursor. The method comprises the following steps: preparing a metal salt solution, liquid caustic sodaand an ammonia water solution with a certain concentration; connecting a reaction kettle with two liquid caustic soda inlet pipes, a metal salt solution inlet pipe and an ammonia water solution inletpipe, wherein a liquid outlet of one liquid caustic soda inlet pipe is higher than a liquid outlet of the other liquid caustic soda inlet pipe; respectively and correspondingly inputting correspondingsolutions into the four liquid inlet pipes in parallel so as to enable the corresponding solutions to flow into the reaction kettle; conveying the reacted solution in the reaction kettle to an ageingtank for ageing, washing and drying to obtain the nickel-cobalt-manganese ternary precursor. Through the preparation method of the continuous nickel-cobalt-manganese ternary precursor, the prepared lithium-ion battery positive electrode material is high in performance; the yield of the production line of lithium battery products is improved; through a method of pouring the liquid caustic soda intwo liquid inlet pipes, the upper liquid inlet pipe shunts one part of liquid caustic soda and enables the part of liquid caustic soda to enter the reaction kettle; the local pH in the reaction area of the prior art is reduced; the crystal nucleuses can be obviously reduced; and D0 is increased.