Abstract: In this paper,the response surface method is used to analyze the influence of welding parameters on the interfacial fracture mode of resistance spot welded(RSW) joint made of dual phase steel DP600 with 1.4 mm thickness.The results showed that welding current,welding time and holding pressure were the key parameters to the interfacial fracture mode of the RSW joints.The proper welding parameters can enlarge the weld nugget diameter ratio and reduce its sensitivity to welding parameters.The optimized welding parameters were obtained to control the interfacial fracture mode with the consideration of the robustness of welding process which was validated by experiments.