The invention relates to the technical field of flat panel display, in particular to a base plate turnover device for turning over a substrate, wherein the base plate turnover device comprises a main body which comprises a side wall and a base, and the side wall and the base form a space having an opening on one side. Two internal opposite sides of the side wall are provided with a plurality of support grooves, the side of the base adjacent to the side wall forms an auxiliary structure which cuts off the support grooves so that at least one support groove is different in length from the other support grooves on the same side and the corresponding support grooves on two opposite sides of the side wall have the same length.