Datum correction device used before tempered glass forming

The invention relates to a datum correction device used before tempered glass forming. The datum correction device is arranged between an outlet of a glass softening furnace and two ceramic rollers for rolling forming and is used for datum correction for softened glass which is taken out of the furnace. The datum correction device comprises a sliding groove, two racks, two stop bars, gears and rocking bars, wherein the sliding groove is formed in a furnace hole wall of the glass softening furnace, the two racks are positioned in the sliding groove, the gears are arranged at two ends of the sliding groove respectively and mesh with the two racks respectively, the rocking bars are connected with the gears, the stop bars are arranged on the two racks respectively, the rocking bars drive the gears to rotate, and the gears in rotation drive the racks and the stop bars on the racks to move leftwards and rightwards so as to enable the positions of the stop bars to be adjusted leftwards and rightwards according to the shape and the size of the glass. Compared with the prior art, the datum correction device has the advantages that the datum correction device is simple in structure, convenient to operate, high in correction precision and capable of performing datum correction on the softened glass which is taken out of the furnace.