The invention discloses a spot welder hot air circulating system which comprises a welding box, a heating device and an air blower. The heating device and the air blower are arranged in the welding box, the heating device is arranged on an air outlet of the air blower, and an air inlet of the air blower is used for inhaling air inside the welding box. The spot welder hot air circulating system has the advantages of being high in heat efficiency, energy-saving and environment-friendly, and small in welding temperature fluctuation at the same time, effectively guaranteeing quality and stability of products, shortening welding cycle, and improving welding reliability.