The present application relates to a support strip and a mask plate. The support strip includes a main body, an irregular portion, and a clamped portion. The main body has two sides in a first direction and two ends in a second direction. The irregular portion is disposed on the side of the main body. The clamped portion is disposed on the end of the main body. A first central axis of the main body, a second central axis of the clamped portion, and a first main centroid axis of a support portion all extend along the second direction. The second central axis is located on a side of the first central axis adjacent to the first main centroid axis. The first direction and the second direction are perpendicular to each other, and are parallel to a plane in which a top surface of the main body is located.