Application Abstract: Based on the research on double-torch tungsten inert gas welding and laser welding of titanium plates in recent two years,we focused on the research on the complete set of equipment and production technology for the industrial production of welded titanium tubes,as well as the application research of welded titanium tubes in marine environments this year.We set up a multi-functional complete set of titanium tube welding equipment production line,and completed small-scale trial production of welded titanium tube using double electrode,double welding gun and arc-assisted laser welding on this production line.The result shows that this production line can realize the efficient and continuous production of welded titanium tubes,and can achieve various control functions such as laser and arc welding control and real-time observation of welding arc.The microstructure and properties of the welded titanium tubes basically meet the project evaluation index requirements.At the same time,the application research of welded titanium tube in marine environment shows that the constructed method of dynamic seawater corrosion evaluation of welded titanium tube can be used to evaluate the thin-walled welded titanium tube in the low temperature multi-effect distillation marine environment.