Abstract: Occurrence of the helical rolled-mark of the tube after running out of the extractor is deemed as one of the control difficulties as encountered with during operation of the CPE push bench mill.Analyzed here in the article is the development mechanism for the said helical mark.Also studied are the problems staying with the rolling equipment, and their influences on the occurrence of the helical mark.Accordingly, improvement actions are proposed.Based on the analysis,it is regarded that the problem that the enveloping surface as between the tube and the roll is less than 70%can be properly solved by means of increasing both rigidity of the pull bar outer bush and the wear-resistant contact surface,and enhancing the positioning accuracy of the roll as assembled onto the drum,which means,the helical rolled-mark of the tube after running out of the extractor shall be eliminated so as to improve the tube quality,reduce labor intensity,and improving efficiency of roll-change operation.