The invention belongs to the technical field of lithium ion batteries, and discloses a single crystal ternary positive electrode material and a preparation method and application thereof, the chemical formula of the single crystal ternary positive electrode material is LiNixCoyMnzM (1-x-y-z) Oc (at) LiaNdOb, 0 < x < = 0.65, 0 < y < = 0.15, 0 < z < = 0.35, 0 < a < = 6, 0 < b < = 4, 1 < c < = 2, and 1 < = d < 2; m and N are at least one of Zr, Ni, Al, Cu, Co, Sr, Mn, Y, Ti, Mg, Mo, B, Sn, Fe, Zn, Si or W. The single-crystal ternary positive electrode material disclosed by the invention is a single-crystal material with a core-shell structure, and is low in surface residual lithium, stable in internal and external structures, high in energy density and excellent in cycle performance and dynamic performance.