The invention relates to a lithium supplementing method for a lithium ion battery positive electrode. The method is used for supplementing lithium for the lithium ion battery positive electrode. In apositive electrode pulping process, a lithium supplementing material is uniformly mixed with a positive electrode main material, a conductive agent, a binding agent, a solvent and other materials, andthen the lithium battery is prepared through the procedures of coating, rolling, assembling, liquid injecting, formation, capacity grading and the like. Compared with the prior art, the process doesnot need to be changed, and operation is easy; inert atmosphere protection is not needed; no special requirement on the environment is needed; the existing production process and equipment do not needto be improved; the lithium supplementing material is uniformly mixed with materials such as a main material, a binder and a conductive agent in the positive electrode pulping process under the existing production environment, equipment and process conditions; and the additional equipment cost does not need to be increased. The method belongs to 'wet processes for lithium supplement', and dust pollution and safety problems caused by dry processes for lithium supplement are avoided. After the lithium ion battery is supplemented with lithium, the initial efficiency and the battery capacity canbe improved, so that the energy density of the battery is increased.