Abstract: The present disclosure relates to the field of cathode materials, and provides a cathode material and a preparation method thereof as well as a lithium-ion secondary battery, wherein the cathode material comprises: a secondary particle comprising a plurality of primary particles, wherein the primary particles contain an active substance having a chemical general formula of LibNixCoyMzNwO2, where 0.95?b?1.05, 0.8?x<1, 0<y+z?0.2, x+y+z=1, and 0.0001?w?0.003; M is selected from at least one of Mn and Al; N is a metal and a coating layer, which comprises a first coating laver and a second coating laver, wherein the first coating laver is formed on the surface of the primary particles, the second coating laver is formed on the surface of the secondary particles, and both the first coating layer and the second coating laver contain a phosphate compound.