NOVELTY - The method comprises coating a stabilized metallic lithium powder with an adhesive, applying an adherent stabilized metallic lithium powder obtained by the coating step to a substrate having parting property, bringing the substrate into contact with a separator, and transferring the adherent lithium powder from the substrate to the separator. The separator comprises a porous sheet of polyolefin. The substrate is polyethylene terephthalate film, polypropylene film or polyethylene-laminated paper. The adhesive consists of silicone based binders.    USE - The method is useful for preparing a separator carrying a stabilized metallic lithium powder on its surface for non-aqueous secondary batteries, which are useful as a power source for electric automobiles, laptop computers, mobile phones and digital cameras.    ADVANTAGE - The method is capable of simply, effectively and safely preparing the separator with high quality thus improving efficiency, energy density, charge/discharge capacity, lifetime and cycle retentivity of the non-aqueous secondary battery.    DETAILED DESCRIPTION - The method comprises coating a stabilized metallic lithium powder with an adhesive, applying an adherent stabilized metallic lithium powder obtained by the coating step to a substrate having a parting property, bringing the substrate into contact with a separator, and transferring the adherent lithium powder from the substrate to the separator. The separator comprises a porous sheet of polyolefin. The substrate is polyethylene terephthalate film, polypropylene film or polyethylene-laminated paper. The adhesive consists of silicone based binders. The coating step comprises immersing the lithium powder in a dilution of the selected adhesive with an organic solvent, and taking the stabilized metallic lithium powder out of the dilution. An amount of the adhesive coating the lithium powder is 0.01-10 wt.% based on the stabilized metallic lithium powder. The stabilized metallic lithium powder is surface coated with substances.