The invention discloses a ceramic diaphragm with a dopamine-containing composite binder and application of the ceramic diaphragm with the dopamine-containing composite binder in a lithium ion battery, and relates to the lithium ion battery. The ceramic diaphragm with the dopamine-containing composite binder comprises a diaphragm base material, wherein the surface of the diaphragm base material is coated with a protective layer; the protective layer is prepared from ceramic powder and the dopamine-containing composite binder. A method of preparing the ceramic diaphragm comprises the following steps: mixing inorganic particle powder, a water-based solvent and an adhesive, adjusting the pH to 6 to 12, adding dopamine, and uniformly mixing the materials, thus obtaining ceramic slurry; coating a single layer or two layers of surfaces of the diaphragm base material with the obtained ceramic slurry, leaving the diaphragm base material to stand for aging till the dopamine monomer is completely polymerized, washing the diaphragm base material with the water-based solvent to remove impurities, and drying the diaphragm base material to remove the solvent, thus obtaining the ceramic diaphragm with the dopamine-containing composite binder. The ceramic diaphragm with the dopamine-containing composite binder can be applied to the lithium ion battery.