Abstract: In this paper,a repair welding technology experiment is conducted on ZAlSi7Mg alloy carass by using TIG.Metallographic struncture analysis,X-ray testing and mechanical behaviour checkout manifested that the repair welding layer is dense,free of delamination and the carass is hardly deformed.The experiment should be valuable for the repairing of defects of ZAlSi7Mg alloy parts formed in mechanical processing and casting.