A mask device, a mask plate and frame are provided. The mask device includes a frame and a first mask plate. The frame includes an inner edge, an outer edge, and a plurality of mounting grooves. A first mask plate includes a substrate, at least one first mask opening on the substrate, and a plurality of clamping portions protruding and extending outward from at least part of a periphery of the substrate. The plurality of clamping portions are mounted in the plurality of mounting grooves, respectively, so that the substrate is mounted on the inner edge of the frame. A direction along which the clamping portion extends from the substrate to a direction away from the substrate is a first direction, a direction perpendicular to the first direction is a second direction.