Soil moisture plays an important role in European land-atmosphere interaction, and it’s memory provides the potential improving the prediction skill of hot extremes. However, our study finds that the effects of soil moisture on hot extremes over the southern Europe (SE) are modulated by Atlantic Multidecadal Oscillation (AMO). In the warm phase of AMO, the soil moisture deficit in May trends to result in extreme high temperature in following summer, through a positive soil moisture-atmosphere feedback. While in the cold phase of AMO, soil moisture deficit over the SE has less effects on hot extremes. Our results suggest that the projected increasing trend of hot extremes over the SE, induced by global warming, may mitigate in the cold phase of AMO. The increasing occurrence of mega-heatwavesover the SE during the recent global warming slowdown can attribute to the combined effect of warm phase AMO and soil moisture deficit.