In this study the effect of activating fluxes on the penetration depth, microstructure and microhardness of AISI316L austenitic stainless steel were evaluated by three TIG process variations (TIG, A-TIG and FB-TIG) and the results were compared together.. After selecting the optimal flux in the second stage, the effect of that on the penetration depth, microstructure and weld microhardness of  welded 316L austenitic stainless steel by A–TIG and FB-TIG methods, were evaluated and  the results were compared by the sample which was welded by TIG process. At this stage, it was found that the depth and width to depth ratio in FB-TIG method is slightly greater than the other two methods. Also in FB-TIG method, eqiaxed dendritic zone in the center line of weld is slightly greater than in A-TIG method. Study of microhardness of weld in three methods shows that in A-TIG and FB-TIG methods hardness of center line is more than TIG method.