Abstract: In order to study the variation of Austenite grain, the Ti-treated 16Mn steel was multi-pass deformed in Austenite complete recrystallization region at constant rolling temperature, pass reduction and interval between passes. After multi-pass rolled, the Austenite grain reached a limit size d_r. To change deforming conditions will affect the critical amount deformation (Rcrit) required to reach the d_r With the increasing of deformation temperature, Rcrit decreased and d_r increased; At big pass reduction, Rcrit increased and Dcrit decreased; while the affluence of interval between passes on Rcrit and d_r was small. Depending on above mentioned result, a reasonable technical schedule for this steel to be control in Austenite complete recrystallization region is that there must be at least two passes at 950℃ or so and each pass reduction is about 20%.