Abstract: The inplane rotary draw bending process of a kind of thinwalled irregular aluminum tube was studied. Based on the software LSDYNA, a finite element model of rotary drawing bending process for aluminum tube was established, and its reliability was validated by experiment. An evaluation method was proposed to describe the channel distortion of the thinwalled irregular tube with harmonicashaped section. According to the simulation results, the variation laws of the irregular tube channels were revealed. The influences of bending angle, bending radius, clearance between module and tube, and friction on the formability were obtained. The results show that the outside channels are expanded and the inside channels become narrow after the tube bending, and the distortion degree of the channels exhibits a linear distribution. Increasing the bending radius can alleviate the channel distortion, while the bending angle, clearance between module and tube, and friction condition between module and tube have little effect on the channel distortion of the tube.