Abstract: The effect of activating fluxes with single component(SiO₂、CaF₂、TiO₂、Cr₂O₃、NaF) on weld depth to width ratio (D/W) is firstly studied in this paper during the TIG welding of stainless steel.After that, the flux SiO₂ is selected to investigate the effect of coating quantity and welding parameters (i.e.welding current, traveling speed, and arc length) on D/W.The experimental results show that the D/W increases with coating quantity of activating fluxes described above.The depth to width ration of welds made with SiO₂ also increases with increasing welding current, traveling speed and arc length compared with welds made without flux.By applying the activating flux during TIG welding of stainless steel,the weld pool depth to with ratio is greatly improved compared with conventional TIG welding.Therefore,the manufacturing coat and cycle time can be apparently reduced and the activating TIG welding has a better application prospect in welding industry.