According to the theories for stretch reducing process and steel tube plastic deformation,the energy method was used to mesh the rolled deformation zone of the steel tube into the upper limit elements,and an admissible velocity field was constructed to deduce a series of formulas of the inner virtual power consumption of deformed bodies.The rolling force during the stretch reducing process could be obtained by optimizing the upper limit power,which could provide guidelines for a proper choice of the stretch reducing process and devices for steel tube companies,as well as new products and devices. According to the theories for stretch reducing process and steel tube plastic deformation, the energy method was used to mesh the rolled deformation zone of the steel tube into the upper limit elements, and an admissible velocity field was constructed to deduce a series of formulas of the inner virtual power consumption of deformed bodies. The rolling force during the stretch reducing process could be obtained by optimizing the upper limit power, which could provide guidelines for a proper choice of the stretch reducing process and devices for steel tube companies, as well as new products and devices.