Titanium and titanium alloy thick-wall welded tubes are the main components in industries such as seawater desalination and marine engineering. In this paper,the double gun welding method of front DC plasma filler wire welding +post pulse TIG arc is used to explore the high-quality and stable welding process of TA1 welding titanium tube with thickness of 4 mm. The non-coupling plasma welding + TIG welding forms utilize the advantages of plasma arc welding and TIG welding respectively. The results show that with the increase of plasma gas flow rate, the penetration depth of DC plasma wire-filled welding increases,which can achieve good full penetration welding of thick-walled titanium tubes;the rear TIG arc remelts the formed weld seam. With the increasing of TIG welding pulse frequency,the grain size of weld and heat affected zone is reduced,meanwhile the joint performance is also improved.The repairing effect on defects such as undercuts during the pre-plasma wire filler welding process is significantly improved by rear TIG arc. This method not only expands the process window for qualified appearance of weld,but also stabilizes the welding process. The joint strength reaches 354 MPa. Through actual production verification,low-cost high-quality welding production of thick titanium welding tube is realized.