CNC cold bending machine is a new type of equipment for processing and manufacturing tunnel support steel arches. The CNC cold bending machine consists of six parts: base, mechanical transmission, cold bending system, hydraulic system, electrical control system and auxiliary system. When the CNC cold bending machine is working, push the section steel to be cold-formed between the two automatic rollers by the door bracket of the auxiliary system, and activate the hydraulic system to make the hydraulic cylinder push the dovetail groove and the cold-formed roller to cold-press the section steel. When the required arc of the CNC cold bending machine is reached, the hydraulic system is closed, and the mechanical transmission system is activated, so that the automatic roller rolls and moves the section steel smoothly and slowly relying on the friction force, and then the continuous cold bending work is completed. At the end of the cold bending, the mechanical transmission system is closed, and the hydraulic system of the CNC cold bending machine is activated at the same time to recover the hydraulic cylinder. The cold-formed steel can be placed on the door bracket of the auxiliary system. This cold bending work ensures the strength of the raw materials, improves the quality of the supporting steel arch, greatly improves the work efficiency, and the operation is simple and clear. Compared with the press machine, the CNC cold bending machine has outstanding working performance.