Tungsten inert gas welding (TIG) is a fusion welding process that has a wide variety of applications in today's industry. The TIG welding parameters play a very important role in evaluating the quality of a weld. This study's primary objective was to optimize the mechanical properties of TIG welding on stainless steel pipe 304L using a various input parameters, such as amperage, travel speed, root gap, and gas flow rate. Experimental methodology with Taguchi based gray relation analysis conducted to optimize the process parameters of TIG welding process on the material 304L stainless steel pipe welded samples of the dimension 16 pieces of ø89mm*125mm*5 mm. ANOVA was conducted in order to examine the significant of welding process parameters using Minitab 19 software were used. The data was collected by observing, photographing and Hardness and tensile experimental tests results. The obtained result improved the mechanical property of the joints with a parameter setting of welding current150 A, travel speed of 1.5 mm/sec, a gas flow rate of 12 lit/min, and a root gap of 2.4 mm, the optimal hardness value of 108.92 HRB was measured, and the optimal tensile strength of 1224MPa was attained using the following parameters: a travel speed of 1.5 mm/sec, a maximum welding current of 150 A, a gas flow rate of 12 liters per minute, and a root gap of 2.4 mm. The ANOVA result shows as Welding current, travel speed and Gas flow rates are the most significant parameters respectively. Keywords: - TIG welding, mechanical properties, Taguchi-Based GRA, weld