Welding of dissimilar metal between austenitic stainless steel (γ-SS) and, high strength low-alloy (HSLA) steel are widely used in high-temperature applications in power station and petrochemical plants. Fusion welding is one of the most widely used methods for joining of dissimilar metal. Therefore, continuous efforts are made to apply this method for joining of dissimilar metal of various combinations and despite many difficulties encountered. These difficulties include problems associated with microstructure of the weld metal and heat-affected zone (HAZ). Considering the lack of such knowledge some understanding in this regard has been presented in reference to dissimilar Austenitic stainless steel (γ-SS) and high strength low alloy (HSLA) steel under controlled pulsed current GMAW. This paper focus on effect of grain size, microstructure and the width of the heat affected zone by pulsed current gas metal arc welding (PGMAW) of dissimilar γ-SS and HSLA steel. The observations show that in PGMA welds, the decrease in grain size at heat affected zone and lower HAZ Width in both HSLA steel and γ-SS especially with the lowering of summarized influence of pulse parameters factor () at similar heat input per unit length of weld (Ω) has been observed.