The invention relates to a novel method for preparing a conductive metal protective layer through an atmosphere pressure plasma film deposition technology. The novel method includes the steps that work gas generates plasmas under the triggering of a high-frequency alternating power source, and a silicon oxide thin film deposits on the surface of a copper plate at the tail end of a jet gun in the mode of a plasma torch. The obtained silicon oxide thin film has good insulating performance and corrosion resistance, and can serve as protective materials for a busbar and other metals.