Abstract: In case of producing the Φ108~146 mm seamless steel tube with the Φ185 mm blank pipe,the production capacity of the Φ177 mm PQF mill is limited due to such shortcomings as the small mass of the blank pipe,high tool-change frequency,so much equipment adjustment work,and high failure rate,etc.The slight stretch-sizing(reducing)process of the said PQF mill is studied.Accordingly relevant technical data of the mill are designed,including the pass,the stretch,and the pipe wall thickness,the speed,and the mechanical parameters for each individual roll stand.Moreover the calculation of the parameters is edited into programs in the Excel form with relevant math analytical method.The method features simplicity,and being easy to do and revise.