Wrinkling is one of main forming defects of the rotary-draw bending process for thin-walled rectangular aluminium alloy tube, which severely restricts the improvement of the forming quality and forming limit. Therefore, a regression prediction model of the wrinkling wave height is built based on finite element(FE) simulation combined with orthogonal regression analysis, and its reliability is validated by experiments. Then the analytical model of forming limit without the occurrence of wrinkling is derived. The laws of the core number, the clearance between mandrel and tube and the clearance between wiper die and tube affecting wrinkling limit are obtained, and the wrinkling limit diagram for the rotary-draw process of thin-walled rectangular tube is obtained.This research provides basis and guidance for improving forming quality of the rotary-draw bending process for the rectangular tubes in production.