According to the machining of reinforcing bar connection thread, the automatic control system is adopted to realize the automatic and uninterrupted machining process of reinforcing bar thread. The thread can be processed on both ends of steel bar. It can upsetting the processing part of the reinforcing bar thread when the reinforcing bar needs higher connection strength, so that the thread of the reinforcing bar increases and the thread connection strength is increased. After the reinforcement thread processing is completed, the grinding process can be carried out to the end face of the steel bar, so that the burr of the steel bar end and the screw entry barrier can be removed to improve the quality of the rebar. It can automatically finish the upsetting, wire and grinding process of the steel bar, save time, save labor, save people, high precision and high production efficiency. It can realize automatic and uninterrupted processing of pipeline steel.