The invention discloses a polishing film and the preparation method, which adopts the ultrafine micro mist as the grinding material and prepares in flow-casting coating method, namely the powdered or granular resin is dissolved into the organic solvent and then added in functional additive to make the resin adhesive, then the abrasive of surface-modified ultrafine micro mist is added into the resin adhesive and the spread coating liquid can be obtained after fully mixing, finally the paint is painted on the surface of soft base in flow-casting coating method and the polishing film can be obtained after drying and curing. The preparation method of the polishing film has the advantages of small equipment investment, simple operation, high productivity and automation level, steady craft, even film performance and low manufacturing cost. The polishing film can adjust the craft parameters of the flow-casting craft conveniently according to the different quality requirement and standards of the products, and can achieve production in multi-specification and small lot production and overcomes the problems that the rapid transformation of the product specification is difficult due to the limit of the equipment structure in roller coating method.