The invention discloses a method for preparing a lithium nickelate cobaltate manganate cathode material by taking waste lithium ion batteries as a raw material. The main points of the technical scheme comprise that an organic acid citric acid is mainly taken as a leaching agent and a gelata, a sol-gel process is employed for preparation of the lithium nickelate cobaltate manganate cathode material, and the specific preparation steps are disclosed. The method helps to avoid pollutions of S, N, chlorine and the like caused by inorganic acid leaching agents employed in conventional methods, helps to avoid by-product generation in metal ion separation process, the whole preparation process helps to avoid a high-temperature calcining link, and the method is low in energy consumption, green, environment-friendly and low in cost; and the prepared product can be returned to factories for sequential use.