The transverse bowing greatly affects accuracy of the roll forming asymmetric corrugated channels (ACC). In order to control this defect, the paper first elucidates its mechanism of the production. Then the transverse bowing is explored by finite element method (FEM) using ABAQUS 2016 software and the effects of the forming parameters are analyzed. Also, a linear regression model is built using Minitab 19 software to evaluate their effects, of which standard values are measured by Pareto chart. It is observed that the number of forming channels has the greatest effect, followed by the roll gas and bending angle, and the friction coefficient has the least. Finally, to decrease the transverse bowing defect (TBD), the dominant forming parameters are optimized according to the evaluation results and the operating conditions. And the results of simulation and optimization are verified by experiments, respectively. This research shows that the TBD can be greatly controlled by the optimization of three dominant forming parameters including the roll gap, bending angle and inter-station distance for given ACC.