The present invention discloses a lithium-rich positive electrode material surface modification method, a positive electrode containing the surface-modified lithium-rich positive electrode material, and a lithium ion battery, wherein the chemical formula of the lithium-rich positive electrode material is xLi2O.yMOb, wherein M is at least one selected from Mn, Ni, Co, Al, Cr, Fe, Ti, Mg and Cu, the ratio of x to y is more than 0.51 and is less than 0.95, and b is more than or equal to 1 and is less than or equal to 2. The surface modification method comprises at least three steps: 1) adding the lithium-rich positive electrode material to an aqueous solution with the pH value of less than or equal to 7, and continuously stirring to obtain a slurry; 2) drying the stirred slurry, and carrying out a heat treatment to obtain powder; and 3) dispersing the powder in a solution containing cladding ionic fluorine, adjusting the pH value of the slurry to 6-9, carrying out a precipitation reaction, drying the slurry after the reaction, and carrying out a heat treatment to obtain the surface-modified lithium-rich positive electrode material. With the method of the present invention, various electrical properties of the material can be comprehensively improved, and the material can meet the development requirements of high power electronic devices. According to the present invention, the process is simple, the cost is low, and the method is suitable for large-scale industrial production.