The invention discloses a lifting device and a lifting method for a neutron beam window maintaining platform working under irradiation. The lifting device comprises a bottom plate, wherein the two ends of the bottom plate are equipped with a steel wire rope winding device and a drive device for driving the steel wire rope winding device; the middle part of the bottom plate is equipped with an electric wire for taking and placing a neutron beam window maintaining platform and a wire tube storage device for a gas tube; a lifting wheel and a supporting base are arranged on the steel wire rope winding device; the lifting wheel is arranged on the supporting base through a lifting wheel shaft; a plurality of threaded slots are formed in the lifting wheel; a lead screw is arranged at one side ofthe lifting wheel; a screw shaft ring sleeves the lead screw; a guide sleeve is arranged on the screw shaft ring; and the guide sleeve is adaptive to a threaded slot in the lifting wheel. According tothe lifting device disclosed by the invention, the steel wire rope is uniformly wound on the lifting wheel back and forth through the steel wire rope winding devices, so that problems such as disordering, inclined pulling, winding and stacking are avoided, and therefore, lifting balance and stability can be improved, irradiation accumulated dose of the lifting device and an operator is shortened,and the application prospect is wide.