A mask plate and a mask sheet are provided. The mask plate includes a first mask sheet and a second mask sheet, the first mask sheet includes a first mask area located in a middle region of the first mask sheet and first peripheral areas located on both sides of the first mask area in a first direction, a thickness of the first mask area is less than a thickness of the first peripheral areas to form a first concave portion; the second mask sheet includes a second mask area located in a middle region of the second mask sheet and second peripheral areas located on both sides of the second mask area in a second direction, a thickness of the second mask area is less than a thickness of the second peripheral areas to form a second concave portion.