The invention relates to a membrane-forming method, which comprises the following steps: providing a membrane-forming apparatus which comprises an accommodation tool, a fixation tool and an ultraviolet light solidification part, wherein the accommodation tool employs a transparent material to produce an accommodation tank; absorbing a part to be filmed by the fixation tool and suspending in the accommodation tank, forming a gap between the part to be film and the wall of the accommodation tank; filling a solvent-free ultraviolet light solidification glue in the gap, wherein the adhesive force between the solvent-free ultraviolet light solidification glue and the part to be film is greater than the adhesive force between the solvent-free ultraviolet light solidification glue and the accommodation tool; solidifying the solvent-free ultraviolet light solidification glue by the ultraviolet light solidification part so as to form a film layer on the surface of the part to be film; separating the part to be film with the film layer and the accommodation tool, and obtaining the part with the film layer on the surface.