Abstract: The measured torsion of the multi-roll section straightener is analysised. The cause and effect of negative torsion is investigated. It is concluded that the overload of the transmission shaft is principally caused by the negative torsion resulting from the torsion interference. The straightening technology involving vational distribution of different roller diameters and using No3 driven roller is presented. The torsion of the transmission shaft and the straightening noise could be redued sighificantly when this technology put into effect in Panzhihua Iron & Steel Co.