Abstract: With the aid of FE code MARC/Autoforge, a thermo-mechanical analysis of the tube round during two-roll rotary rolling process was studied. From the simulation, the field of strain and stress and the distribution of temperature are respectively obtained. The W-shaped distribution pattern of deformation on the longitudinal section of the round, which was obtained from physical simulation experiments, is further verified and the reason causing the W-shape is discussed in detail. Some divergences of views in the mechanism of center-crack forming are clarified, and a new distribution feature is discovered. The hydrostatic pressure in the center of the round is of positive larger value.