In this study, pre-coated material was applied in roll-bending process to make 90 degree wall angle with various corner radii. Based on the desired corner radius value, a die radius and bending angle should be selected to obtain corrected shape. To predict spring back in roll-bending process, combined kinematic/isotropic hardening law was used and shown more accuracy with other laws when comparing with corresponding experiment data. To decide die radius and bending angle for desired shape, several values of die radius and bending angle of roll bending process were first changed to simulate and investigate corner radius and wall angle of blank after spring-back. A MATLAB tool was then utilized to determine the corner radius and wall angle of blank after spring-back as functions of die radius and bending angle using a surface fitting method. Finally, the die radius and bending angle were obtained by solving intersection curve equations between desired planes of corner radius and 90 degree wall angle with fitted surface.