【Objective】The increasing frequency of global drought events has significantly affected the structure and function of forest ecosystems. This study aims to estimate the effects of drought on contents of particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) at different soil depths in poplar plantation, providing a theoretical basis for predicting the responses of forest soil organic carbon (SOC) and its stability to drought in the future.【Method】We took a 10-year-old poplar plantation in Dongtai Forest Farm, Jiangsu Province as the research object. In August 2018, three drought treatments for reducing throughfall were set up: i.e., a control treatment (CK), a moderate drought with reduced 30% throughfall (D30%), and a severe drought with reduced 50% throughfall (D50%). Three replicate sample plots were set up for each treatment with a total of nine sample plots. After four consecutive years of field controll experiments, soil samples were collected in July and November 2022, and February and April 2023 in each drought-treated sample plot to determine soil POC and MAOC contents in the growing (July 2022) and non-growing (February 2023) seasons, as well as soil physicochemical properties such as SOC, dissolved organic carbon, microbial biomass carbon, and readily oxidizable organic carbon in these four periods. Based on ANOVA, correlation analysis, and redundancy analysis, we quantified the characteristics of changes in soil POC and MAOC under drought stress and analyzed the key factors driving the variation in their contents.【Result】Drought had no significant effect on soil POC content, while its impact on soil MAOC content was constrained by season, drought degree and soil depth. Specifically, during the growing season, moderate drought (D30%) significantly increased the MAOC content in the surface soil [0,10)cm, while both drought treatments (D30% and D50%) significantly decreased the MAOC content in the middle soil layer ([10,20)cm) and lower soil layers ([20,40) cm). During the non-growing season, both drought treatments (D30% and D50%) significantly reduced the MAOC content in the surface soil, but had no significant effect on the middle and lower soil layers. Vertically, the soil POC and MAOC content decreased significantly with soil depth. The correlation results showed that POC and MAOC content were significantly and positively correlated with most soil physical and chemical properties, while were significantly and negatively correlated with bulk density and carbon to nitrogen ratio(C/N). Redundancy analysis indicated that soil microbial biomass carbon was the key factor driving the dynamic changes of soil POC and MAOC content under drought.【Conclusion】Drought had no significant effect on soil POC content in the poplar plantation; however, it significantly altered soil MAOC contents, and the effect was constrained by factors such as season, drought degree, and soil depth. This study suggests that when predicting the response of forest soil carbon pool stability to drought in the future, factors such as season, drought degree and soil depth should be fully considered.