The purpose of the present work is to explore the evolution mechanism of highly oriented materials obtained from one-stage solid die drawing (SD) process and two-stage solid die drawing (TD) process. This study focuses on structure evolution and orientation mechanism of isotactic polypropylene during the two different process routes. During solid die-drawing process, the sample drawn through a conical die by an axial load undergoes die drawing and inevitably undergoes free drawing after leaving the die exit. Both die drawing and free drawing make contribution to final crystallinity, orientation and properties enhancement. Because the structure and orientation of sample are quite different in different location, it is important and required to thoroughly investigate the effect of die drawing and free drawing outside the die on one-stage die drawing and two-stage die drawing processing. The results showed that there was a great difference between the orientation mechanism and structure evolution of two-stage solid die drawing process and one-stage solid die drawing process. All samples would undergo free drawing process after die drawing process. Die drawing and free drawing process were of equal importance to one-stage die drawing process while die drawing process showed an prominent contribution to the two-stage die drawing process. Drawing speed showed beneficial influence on die drawing process for both single- and two-stage die drawing process routes. Under the same processing condition, tensile strength and modulus of samples prepared by two-stage die drawing process were found to be higher than those prepared by single-stage die drawing process and the maximum value could reach 241.93 MPa and 3.57 GPa, respectively. Moreover, two-stage die drawing samples showed better dimensional stability than single-stage die drawing samples especially under low draw rate.