NOVELTY - A super-molecule film preparing method involves performing plasma treatment on a polyolefin membrane surface with carboxyl under 80 w carbon dioxide plasma powder, leaching the membrane in Poly(ethyleneimine) aqueous solution, and rinsing with deionized water. The deionized water, methanol and ethanol as a solvent are formulated in an organic building element. The amidogen and carboxylic acid radical are formulated in an inorganic building element followed by assembling the polyolefin membrane, organic building element and the inorganic building element to prepare a super-molecule film.    USE - Method for preparing a super-molecule film that is utilized in a lithium ion battery diaphragm.    ADVANTAGE - The method enables preparing the super-molecule film with improved stability, high machinery strength, ion conductivity and electrochemical property.    DETAILED DESCRIPTION - A super-molecule film preparing method involves performing plasma treatment on a polyolefin membrane surface with carboxyl under 80 w carbon dioxide plasma power at flow rate of 20 ml/minutes for 60 seconds, leaching the membrane in Poly(ethyleneimine) aqueous solution for 20 minutes, and rinsing with deionized water for 3 times. The deionized water, methanol and ethanol as a solvent to concentration of 0.01-1 mg/ml are formulated in an organic building element such as multi-poly-dopamine, polyethyleneimine, polyallylamine hydrochloride, polyacrylic acid, hyaluronic acid, sodium alginate and chitosan. The amidogen and carboxylic acid radical to concentration of 1-10 mg/ml are formulated in an inorganic building element such as zirconium dioxide, silicon dioxide, aluminum oxide and polyhedral oligomeric silsesquioxane to particle diameter of 5-25 nm. The pre-treated polyolefin membrane, organic building element and the inorganic building element are immersed in deionized water for 1 minute followed by assembling the polyolefin membrane, organic building element and inorganic building element to prepare a super-molecule film to thickness of 50-200 nm after soaking the polyolefin membrane in 1-ethyl-3-carbodiimide hydrochloride and N-hydroxy succinimide as crosslinking solvent for 12-24 hours.