The present paper focuses on fatigue modeling of resistance spot-welded (RSW) joints. Fatigue tests are performed on aluminum RSW joints and fatigue data are generated. Stress intensity factors at nugget circumference are calculated based on loads transferred by weld nugget. An equivalent stress intensity factor Keq is defined and modified to correlate fatigue test results. Keq modified by critical crack length is proven efficient in consolidating a large amount of fatigue data with correlation result significantly improved. Practical potentiality of this model in automobile body structure fatigue analysis is discussed. The proposed model could be readily applied to structure fatigue analysis.