In present research, response surface methodology (RSM) is used to investigate the effects of control parameters on critical responses in resistance seam welding (RSW) process. Four critical controllable input variables, weld pressure, weld current, overlapping and material thickness were selected to analyse the effects on the responses weld time (T_w), surface roughness (R_a) and hardness (H) in RSW. Central composite design (CCD) array is selected to conduct the experiments and to estimate the model adequacy test in RSW. Correlation coefficient (R²) values were observed for surface roughness, weld time and hardness, respectively. Responses were optimized using critical variables weld pressure, weld current, material thickness and overlapping, respectively, with influence of RSM. The optimal process parameters are introduced and tested in industrial environment.