A weld joint automatic tracking control method and system based on magnetic controlling arcs and laser vision sensing mainly solves the technical problem that an existing space weld joint is low in automatic real-time tracking accuracy, not good in system fault tolerance and the like. According to the key points of the technical scheme, all deviation information, obtained by a magnetic controlling arc sensor (10) and a laser vision sensor (11), of the butt welded seam center of a welding gun (1) is input to a tracking system central control unit (8), information processing is conducted through a double-sensing estimating, examining and correcting fusion method, infused deviation information is taken as weld joint deviation regulating amount of an executing mechanism, the executing mechanism executes weld joint deviation regulating, weld joint automatic tracking is achieved, and the automated welding is completed. The weld joint automatic following control method and system is mainly used for weld joint automatic tracking.