The invention discloses a preparation method for gradient coated LiNiO2 for lithium ion battery positive pole material, so as to solve the problem of bad circulating performance of conventional LiNiO2. The molecular formula of the LiNiO2 is LiNi 1-xMxO2, wherein, the x is less than or equal to 0.3 and greater than 0, the M is adulterated metal ions and is one or more selected from magnesium, nickel, Fe, titanium, zinc, Co, manganese, aluminum, Nb and vanadium, the gradient coat refers to that concentration gradient hydroxide coprecipitate provided with nickel and other metallic elements is coated on the surfaces of spherical nickelous hydroxide material, and then the precursor is mixed with lithium-source material and roasted under high temperature in an oxygen atmosphere furnace, so as to obtain high-performance modified LiNiO2. The gradient coated LiNiO2 obtained in the invention has the characteristics of high specific capacity, excellent circulating performance, excellent high-temperature property and the like, and is suitable for the application field of high- capacity lithium ion batteries.