The hot rolled plates of TC4 titanium alloys were welded by friction stir welding. The wear of tool of DZ22 superalloy stirring head characterization was carried out by weight loss measurement, 3D photographic technique and microscopic observations during friction stir welding of TC4 titanium alloy. This experiment has been studied Influence of welding distance tool wear in friction stir welding of TC4 alloy. The results indicate that severe tool wear deformation occurred after welding 180mm. The wear of tool is positively correlated with welding distance. The length of tool pin was shortened by 0.24mm and the wear rate was 0.97%. The depth of tool shoulder was shortened by 0.4mm and the wear rate was 1.73%. The weight of tool was reduced by 0.15g and the wear rate was 0.74%. In the process of friction stir welding of TC4, high temperature and high pressure are the main reasons for the wear of tool.Tool wear types are mechanical wear and tear、abrasive wear、adhesion wear and oxidative wear. The wear of tool is usually the result of the interaction of these wear. The wear of tool will pollute the FSW joints and form defects, thus affecting the performance of the FSW joints.