Abstract: Different annealing systems were selected to heat treat the Φ102 mm×0.5 mm×380 mm large caliber thin-walled titanium welded pipe, and then the local deformation of the weld was processed.Mechanical properties, technological properties, microstructure and hardness at different positions were compared and analyzed. It's found that the proper heat treatment system can effectively improve the elongation of weld of the large caliber thin-walled titanium pipe and significantly reduce the hardness difference among the heat-affected zone, weld and base metal. When the deformation rate of reprocessing reaches 35%,the saw-tooth structure in the weld will transform into equiaxed structure.