Abstract: A ternary precursor of a lithium ion battery as well as a preparation method and preparation device thereof are provided. A chemical general formula of the ternary precursor is NixCoyMnz(OH)2, 0.5?x?0.9, 0.05?y?0.3, and x+y+z=1. A particle size D50 of a large-particle ternary precursor is 10.0-16.0 ?m, a particle size D50 of a small-particle ternary precursor is 3.0-6.0 ?m, and a span is 0.2-0.8. A nucleation and growth process of a crystal is regulated through a staged EDCF, a crystal particle size meeting specific requirements and compact particles without a cracking phenomenon can be obtained. A disc, inclined blades and an arc surface are combined, and an arc-shaped curved surface can effectively reduce a turbulence energy dissipation rate of a local area.