The invention discloses a method for a nanoparticle-coated nickel lithium manganate positive electrode. The technology is relatively simple in process, small in energy consumption, low in cost and high in production efficiency and is easy to operate, industrialization on a large scale is easily achieved, and the product is high in specific capacity and long in cycle lifetime. Ion bond-modified magnesium oxide nanoparticles can be uniformly dispersed in the positive electrode material, crystallization of a polymer matrix is effectively prevented, and the improvement of ion conductivity is further guaranteed.