Abstract: Elaborated are the strength parameters of the large-sized piercing mill of the newly-built Φ720 mm Pilger Mill Plant as located at Sichuan Sanzhou Special Steel Tube Co.,Ltd. A precise piercing load math model is set up via such activities as relevant theoretic analysis,and acquisition,regression and studies of the actual production data,and thus all the elements as influencing proper control of the piercing load are analyzed. The effectiveness of using the research result in the rolling operation has led to such as conclusion that the research achievement has certain instructive significance for the large-sized piercing mill in terms of calculation,control and setting of the piercing load.