The effects of process parameters of GTA welding on weld distortion, depth of penetration, micros hardness, tensile strength and microstructure of welded joints of stainless steel plate of AISIs 304s stainless steel has been studied. The optimum combinations of process parameters has been suggested to achieve minimum weld distortion, maximum depth of penetration (DOP) of welds bead and micros hardness. Design of experiment (DOE) was used to plans and design the experiment to study the effects of TIG welding parameter on both mechanical and metallurgical properties of AISIs 304 stainless steel. The input parameters considered in present investigation were welding current, gas flow rate, root face and welding speed. L9 Orthogonal Array (OA) techniques was used to formulate the experimental layout. It was concluded that the minimum weld distortions were founds at optimal setting of parameters of welding current (90 A), gas flow rate (10 LPM), root face (1 mm) and welding speed (31.578 mm/min) and the optimum response value is 2.3996 mm. Welding speeds (WS) is the most significant parameter for distortions during GTA welding. Welding current (A) is the most significant parameter for depth of bead penetration (DOP) during GTA welding. The recommended parametric combinations for optimum depth of bead penetrations is welding current (110 A), gas flow rate (10 LPM), root face (1.5 mm) and welding speed (31.578 mm/min.) and the optimum response value is 5.6961 mm. The micro hardness is maximum at I=90A, GFR=1.5lpm, RF=1.5mm, WS=21.428 mm/min. for both heat affected zone (HAZ) and welds zone (WZ). The highest and lowest values of tensile strengths were founds in sample no.4 and sample no.7. The experimental and predicted value were found in goods agreement. In addition to this the microstructure of base metal (BM) consisting of equiaxed austenite grains with annealing twins with in austenite grains. The welds were found free from porosity, internal cracks and lacks of fusion. Microstructure shows precipitation of carbides particles at grains boundaries. The specimens from the weld metal founds dendritically cored structure containing some deltas ferrite and precipitated small carbide particles.