The invention provides a nickel-cobalt-manganese ternary positive electrode material and a preparation method and application thereof. The nickel-cobalt-manganese ternary positive electrode material is LiNi<0.8>Co<0.1>Mn<0.2>O<2>, and the surface with primary particles of the nickel-cobalt-manganese ternary positive electrode material is coated with lithium boron oxide. The preparation method comprises the following steps: dispersing a nickel-cobalt-manganese ternary precursor into an alcohol solution, and performing stirring and mixing to form a solution A; adding boric acid into water, and stirring until the boric acid is completely dissolved to form a solution B; adding the solution B into the solution A, stirring, heating and drying by distillation to obtain solid powder; and mixing the solid powder with lithium salt, and calcining to obtain the nickel-cobalt-manganese ternary positive electrode material. The coating substance H3BO3 is dissolved in an aqueous solution, enters gaps of secondary particles of the ternary precursor, is separated out among the primary particles in the solvent evaporation drying process, and is then fired, so that coating of the primary particles is realized, generation of microcracks of the primary particles can be effectively inhibited, and the cycle stability of a battery is improved.