The clearance and friction have large influence on wrinkling in rotary draw bending process of thin-walled rectangular tube. In this paper, a three-dimension Al FEM model of rotary draw bending of thin-walled rectangular tube is built under the ABAQUS/ Explicit environment. Based on the model, simulation and analysis of rotary draw bending for aluminum alloy 3A21 thin-walled rectangular tube have been carried out. The results show that the height of wrinkling wave decreases obviously with the decrease of the clearance between mandrel and tube or with the increase of the friction coefficient between wiper die and tube; however, the effect of friction coefficient on wrinkling becomes weaker while increasing the clearance between mandrel and tube. The achievements of this study provide a guideline for determining the process parameters for thin-walled rectangular tube in rotary draw bending process.