Al-Li alloys show extraordinary specific strength and have been used in Space Shuttle SLWT(Super Lightweight Tank) with application of Friction stir welding (FSW). FSW has many advantages like the absence of porosity, distortion and residual stresses which are typical defects of the fusion welding processes. The process uses a rotating tool with a profiled pin that penetrates the parts to be joined; the tool then starts to travel along the joint line. By keeping the tool rotating and moving it along the joint line to be welded, the softened material due to the frictional heat is stirred and mechanically mixed together by the rotating pin forming a weld in solid state without melting. The present work is to investigate the effect of tool configuration on the microstructure and mechanical properties of friction stir welded AA2195. Since the mechanical properties of the joint are related with development of microstructure evolution during FSW, microstructure and mechanical properties of joints were investigated for different tool configuration.