Abstract: Microstructure characteristics of repairing welded joint of TA15 Ti alloy were analyzed by optics microscope,X-ray diffraction and electron probe microanalysis.The feasibility of Ti alloy multiple repairing welding was discussed.It was found that repairing welding was the process to form the new bead and heat-affected zone on the original bead.The interface quality of repairing welding bead and original bead is good and the defects,such as interphase reactants,air hole,crack and sediment,were not observed between the repairing welding layer and the original bead.Elements Ti,Al,V,Fe were distributed uniformly from repairing welding bead to the base metal.Repairing welded joint structure in the room temperature was α-Ti.As repairing welding times increased,crystal grain grew up and dentate α-phase appeared.Micro-hardness in repairing welding region tended to decrease to some degree.The results showed that repairing welding of TA15 Ti alloy was feasible.