The bending technics of workpiece with U-type groove was analysed,and a brake die with both flexible ears on the upper die and sidesway on the roller-type lower die was introduced. The upper die with both flexible ears which steered clear of U-type groove when bending solved the bending problem of workpiece with a U-shaped grooves. The sidesway on the lower die which only bent the shorter hem of workpiece reduced the operational difficulty. The design of roller-type on the lower die improved the surface quality of the workpiece. The bending and spring back of blank were simulated by ABAQUS. The key parameter and processing technic of the brake die were studied.