The invention relates to the field of lithium electric energy and provides a method for preparing a lithium cobalt oxide cathode material of a lithium ion battery by a freezing crystallization method. The method comprises the following steps: respectively preparing an additive solution and metal salt solutions of Ni, Co, Mn and Li; adding the solutions into a freezing crystallization kettle with proper reaction conditions; enabling the Ni, Co, Mn and Li solution to be precipitated in the freezing crystallization kettle; filtering turbid liquid, using filtering fluid as a mother solution, carrying out secondary freezing crystallization, and drying a crystallization substance to obtain Ni, Co, Mn and Li salt powder; calcining the Ni, Co, Mn and Li salt powder to obtain the lithium cobalt oxide cathode material of the lithium ion battery. According to the method disclosed by the invention, by means of the freezing crystallization method, the speed and size of crystallization can be controlled by influencing the crystallization speed of Ni, Co, Mn and Li elements, and the properties and the performance of a synthetic material are favorably regulated and controlled; in addition, uniform distribution and stable product properties of multiple metal elements of lithium cobalt oxide are realized, so that the properties of the lithium cobalt oxide cathode material disclosed by the invention are more excellent than those of the lithium cobalt oxide cathode material on the current market.