The invention discloses a low-temperature vacuum film plating method. A substrate material is cleaned; the cleaned substrate material is put in a vacuum evaporation chamber; inert gas is adopted as a cleaning source to clean the substrate material again; a low-melting-point target is adopted to perform the vacuum evaporation film plating treatment for the substrate material under the conditions of 10-5-10-4 Pa, the reaction pressure of 0.4-0.8 MPa, the reaction distance of 7-10 cm, the target temperature of 150-400 DEG C, the evaporation speed of 1.2-1.8 g/m3.s and the substrate temperature of 110-150 DEG C; and ultraviolet rays are adopted to perform the photocuring treatment for the treated substrate material. The low-temperature vacuum film plating method realizes the film plating for various high molecular substrates under the condition of lower temperature, and can fully satisfy actual demands.