Drought poses a significant threat to economic and agricultural development,impacting physical health and daily life.With global warming,heatwaves,and droughts,extreme events are occurring with increasing frequency,exacerbating disaster risks.The middle-lower Yangtze Plain,one of China's most densely populated,economically developed,urbanized regions,experienced the most severe heatwave and drought-compound extreme event since 1961 in 2022.This event significantly impacted energy supply,agricultural production,and the ecosystem.This study analyzes precipitation and evaporation characteristics during the flood season from 2000 to 2022,exploring the mechanism and evolution of the 2022 extreme drought event in the middle-lower Yangtze Plain.A comparison with the high-temperature and drought events in 2013 provides a deeper understanding of the relationship between high temperatures and extreme drought in this region.The hydrological drought index,net precipitation(precipitation minus evapotranspiration,P-E) is used to analyze the drought conditions.Using ERA5 and ERA5-LAND reanalysis data,changes in P-E are decomposed into dynamic,thermodynamic,and transient eddy componentsby analyzing the moisture flux budget.Surface temperature during the 2022 flood season increased by nearly 1 ℃ compared to the 20-year average(2000—2019),with temperatures rising over 2 ℃ from July to August.Precipitation during the flood season decreased by 37％ and by 45％ from July to August,respectively,compared to the average for the same period.Net precipitation analysis indicates that the drought was primarily caused by decreased precipitation in the early flood season(May—June) of 2022.Moisture flux budget decomposition shows that changes in transient eddy and mean circulation were major contributorsto the early drought.In the mid-period(July—August),high temperatures enhanced surface evapotranspiration,especially in bare soil,worsening the drought.The thermodynamic contributionfrom increased specific humidity,driven by temperature rise,was the greatest factorin drought intensification.In the later period(September-October),high temperatures further altered the average circulation,with the dynamic component extending the drought duration.In contrast,the 2013 high-temperature and drought event was initially dominated by thermodynamic contributions,with mean circulation and transient eddy changes intensifying the mid-period droughtand only thermodynamic contributions remaining later,resulting in shorter duration and weaker drought severity.This analysis of the 2022 heatwave and drought compound extreme event development and evolution in the middle-lower Yangtze Plain provides a reference for predicting and warning about high-temperature and drought extreme events in humid areas.In-depth research on these development and evolution events can improve regional drought event prediction and duration forecasting.