A method of a preparing double-layer antimicrobial coating comprises: placing a plastic substrate into a PVD vacuum equipment for a vacuum process rinsing and activating the substrate when the vacuum level reaches 10−2 coating a metal film onto the activated substrate by the vacuum process spraying an antimicrobial intermediate coating onto the metal film and then coating an antimicrobial metal film by PVD to obtain a double-layer antimicrobial layer. The coating has two antimicrobial layers, and includes bores because the density of the coated film layer produced by PVD is low, so that the antimicrobial agent of the antimicrobial intermediate coating can pass through the bores and move to the surface of the coating and the surface of the antimicrobial coating, so as to kill the bacteria or suppress their grown. The method is very suitable for the sanitary, electronics, electrical appliances and the automobile industry.
