Method and device for protecting paper sheet

The present invention relates to a device for protecting paper sheet, including the following. A mist treating system, includes a working cover and a suction port provided on the working cover. A metal base plate is capable of being drawn out from an outlet of the working cover. An inlet and an outlet are provided on the sidewall of the working cover. An insulating layer provided at the top surface of the metal base plate. A sliding rail is provided above the metal base plate. A sprayer is used for applying an atomized deacidification agent to a paper sheet. A discharging electrode is used for discharging to the paper sheet on the insulating layer. The working cover is covered outside of the metal base plate, the insulating layer, the sliding rail, the sprayer, and the discharging electrode. A plasma power supply is used for generating linear plasma.