In this research is to study the influence parameters affecting the mechanical property (microhardness) and optical investigation (microscopy) of austenitic stainless steel grade (AISI-304L& AISI-310) with Gas Metal Arc Welding (GMAW). The research was applying the different values of wire speed and current for experiment, which have following interested parameters: welding current at (180, 250 and 320 Amps), welding wire speeds at (2, 3, 5 m/min), shield gas pure CO₂ and (24V)Welding Voltage. The study was done in following aspects: microhardness and optical investigation. A research study investigate the maximum value of micro hardness for welding joint is 444.9 Hv at wire speed 3m/min and 250 Amps welding current. From the microscopy that HAZ has finer grain and interdendrictic austenitic phase at wire speed 3m/min & 250 Amps current which may cause the high tensile strength & micro hardness.