Abstract This study discussed software engineering that was easier to predict the stress and strain curve of a dissimilar weld joint. The objective of study could be used to predict dissimilar weld joint with the difference properties. The dissimilar weld joint in this study is stainless steel 304 and Carbon Steel 37 that have mechanical properties near same. GUI and Numeric model to develop the loading distribution have been also studied. Each process of tensile testing and specimen response uses a mathematical equation which is changed to the program discussion. Software engineering to predict the stress and strain curve succeeded to develop. Stress and strain curve of the software results have been compared with the experiment results. The conclusion of this study that curve displayed by the prediction software shows the suitability of the stress-strain curve, the numerical method used in this study is adjusted to the conditions that occur when the tensile test is carried out. The simulation results of the tensile test on dissimilar welding between stainless steel 304 and carbon steel 37 show a fairly good fit because they display a stress-strain curve that matches the stress calculations obtained during the experiment.