The invention relates to a bending die. The bending die comprises a convex die, concave dies which are correspondingly distributed at two sides of the convex die, a convex die fixing device, combinedconcave die fixing devices, a spring-back stopping element and a guide device. According to the bending die, the spring-back stopping element is used for controlling the spring-back angle of a workingworkpiece after forming, and the spring-back stopping element is positioned right above a positon where a horizontal working part of each concave die is in transition connection with a second circular arc working part, and thus the bending workpiece can be formed in one time, and as a result, the defect of modifying and debugging the bending workpiece in a plurality of times after forming can beavoided; an adjusting gasket is arranged between each concave die and the corresponding combined concave die fixing device, and thus the bending part can be formed by different forming angles withoutintegrally replacing the die, and as a result, the cost is decreased, and an existing die is utilized to the maximum; the combined concave die fixing devices are adopted, so that the overall weight ofthe die is decreased, and moreover, the die is conveniently and quickly mounted and dismounted.