The invention belongs to a manganese cobalt nickel three Yuan lithium ionization cell anode material, specifically relates to the lithium manganese cobalt nickel oxygen and its synthetic method. The high-capacity, the high safety performance of other battery positive electrode material is unable to compare with lithium manganese cobalt nickel oxygen, moreover low in price, the good compatibility with the electrolyte, the outstanding circulation performance, will certainly to thrust the market in the recent several years. The chemical formula of lithium manganese cobalt nickel oxygen is: The LiMn1/2Co1/4Ni1/4O2 crystal structure is a hexagonal system. The synthetic method of lithium manganese cobalt nickel oxygen is: (1) preparing the mix solution which is composed by the manganese salt, the cobalt blue, the nickel salt, under the agitation situation, joining the alloy salt brine, the complexing agent simultaneously in the reacting system according to the certain proportion distinction, simultaneously adjusts the join speed of alkali to maintain pH to be constant; After continuous feed certain times, filtrate and wash the precipitate to obtain the forerunner body. (2) Grinding and mixing lithium source element and forerunner body ball, after mixed evenly, compacting, roasting, and decomposing to obtain the lithium manganese cobalt nickel oxygen. Then cooling, grading, mixing to obtain the product.