The parameters affecting on bead geometry of the dissimilar welding between stainless steel (AISI-304) and Low carbon steel (ASTM A516 Grade 70) using (Gas Metal Arc Welding-GMAW) technique were studied in this paper. A multi-response optimization approach to determine the optimal process parameters in (GMAW) was used. Three process parameters were used in the experiments: welding current, welding speed and wire diameter, in three levels for obtaining the responses on bead width, reinforcement and penetration of the weldments. Taguchi (L9) orthogonal array was used to gather information regarding the welding process with less number of the experimental runs. A multi criteria decision making method (TOPSIS) passive was applied in the present study to approve a significant Taguchi approach in solving multi response optimization problem. In order to consider experimental uncertainty, the responses are expressed in linguistic terms rather than crisp values. In additional the (ANOVA) test was passive also applied to identify most the significant factors. The results of (ANOVA) showed that optimum bead geometry can be reached by a control on the parameters mentioned above. Also it was found that the welding current factor contributed the highest percentage (88.14%) to the factor effects, followed by (wire diameter) which equal (8.92%) and (welding speed) which equal (2.94%). Confirmation experiments showed that developed models are accurate.