Abstract: Automatic pulse-GTAW welding experiments are carried out on 5G position of TA16 heat exchange tube. Effects of pulse frequency, pulse width ratio, arc starting position, assembly requirements and adding melting ring on weld formation and inner weld quality are studied. Optimized welding parameters are obtained and the visual test, non-destructive test, metallographic structure, mechanical performance, helium leak detection, water pressure test of welded joints obtained by using optimized welding parameters are carried out.Resultsshow that all indexes of the welded joints obtained by adopting optimized welding specifications can meet the requirements of relevant specifications and technical indexes. The study results can provide certain reference for the alpplication of TA16 heat exchange tube on steam generator.