It has been demonstrated that the loading history takes into account the loading sequence and loading interaction effects. Nonlinear damage models based on fatigue driving stress theory consider the loading sequence but exclude the loading interaction effects. In this study, a novel evolution curve for fatigue driving stress was created by including the loading interaction factor in the equation of driving stress evolution. Through using fatigue driving stress equivalence, the remaining fatigue life under varying amplitude loading was then predicted by an enhanced fatigue driving stress model. Compared with Miner's rule, the K-R model, Zhu's model, and Li's model, this new model gave more accurate and reliable predictions.