The invention discloses a plate processing flattening arrangement device and a use method. The device comprises a bottom fixing plate, the left side of the bottom fixing plate is fixedly connected with a left supporting plate in a perpendicular mode, a group of left shaft holes which are transversely arranged are formed in the left supporting plate, the left shaft holes are connected with left bearings, the right side of the bottom fixing plate is fixedly connected with a right supporting plate, and the right side of the bottom fixing plate is fixedly connected with a right supporting plate ina perpendicular mode, a group of right shaft holes which are transversely arranged are formed in the right supporting plate, and the right shaft holes are connected with right bearings; and the leftbearings and the right bearings are connected through lower transverse shafts, the lower transverse shafts are connected with lower pressing rollers, the lower pressing rollers comprise the lower middle convex pressing roller, a lower middle concave pressing roller and a lower flat pressing roller, moreover, the lower middle convex pressing roller, the lower middle concave pressing roller and thelower flat pressing roller are arranged in sequence, the lower middle concave pressing roller is corresponding to an upper middle concave pressing roller, the lower middle convex pressing roller is corresponding to an upper middle convex pressing roller, and the lower flat pressing roller is corresponding to an upper flat pressing roller. The device and the method are used for plate processing flattening arrangement.