[1]¿p#1 Soil organic carbon (C) constitutes the largest terrestrial C reservoir; however, the mechanistic understanding of its dynamics remains elusive, particularly the role of soil priming effect triggered by root exudate inputs under drought. In this study, we conducted a controlled study by applying different doses of analogue root exudate (quantified through field observations) to soils under two moisture regimes: control (60% water holding capacity, WHC) and drought stress (35% WHC) based on a 7-year throughfall exclusion experiment. Our results showed that soil priming effects decreased dramatically under drought relative to the control. Specifically, the priming effects over 30 days averaged 584 μg CO2 g-1 soil in the control, while drought reduced it by 44%. These changes in soil priming effect were primarily driven by C availability, nutrient stoichiometric imbalances, and microbial properties. Our findings suggest that incorporating mechanistic linkages among root exudates, nutrient stoichiometry and microbial properties into terrestrial biogeochemical models could provide a framework for advancing predictions of rhizosphere priming effects and their implications for soil carbon persistence in a changing climate.