The invention discloses anti-flaming ceramic modified size and a lithium ion battery membrane coated with same. A preparation method of the anti-flaming ceramic modified size comprises the following steps: carrying out surface pretreatment on inorganic particles and a flame retardant by utilizing a silane coupling agent, thus forming anti-flaming ceramic modified powder; then uniformly stirring in a solvent, and carrying out ball milling; sequentially adding a binding agent and a thickening agent, and stirring at high speed, thus forming the anti-flaming ceramic modified size. The lithium ion battery membrane is formed by coating a polyolefin microporous membrane, which is subjected to low-temperature plasma surface modification treatment, with the anti-flaming ceramic modified size. According to the anti-flaming ceramic modified size disclosed by the invention, the problems that a ceramic coating layer is easy to fall off from a membrane and the coating thickness or the surface density is non-uniform are effectively solved; meanwhile, the inorganic particles and the flame retardant in the ceramic coating layer take a synergistic effect, the inorganic particles are used for supporting the lithium ion battery membrane not to shrink when the lithium ion battery membrane is in over-charge heating, and the security of a battery is improved.