The present invention relates to a lithium ion cathode material and a lithium ion battery. The chemical formula of the cathode material is: LiaNixCoyMnzMbO2, wherein 1.0≤a≤1.2; 0.00≤b≤0.05; 0.30≤x≤0.60; 0.10≤y≤0.40; 0.15≤z≤0.30; x+y+z=1; M is one or two or more selected from the group consisting of Mg, Ti, Al, Zr, Y, W, Mn, Ba and rare earth elements; wherein the scanning electron microscope observation shows that, the cathode material consists of secondary particles agglomerated by 10 or less primary single crystal particles and secondary particles agglomerated by more than 10 primary single crystal particles, and wherein, the area percentage of the secondary particles agglomerated by 10 or less primary single crystal particles is greater than 80%, and the area percentage of the secondary particles agglomerated by more than 10 primary single crystal particles is less than or equal to 20%. The lithium battery prepared by the cathode material of the present invention has good cycling performance, the preparation method thereof is simple, and can be conveniently and massively produced.