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Under the influence of global change， drought events have occurred frequently in the originally humid Southwest region since the 21st century， which has inhibited the growth of vegetation in the region to variable degrees and threatened the security of ecological barriers.In this study， we used the Standardized Precipitation Evapotranspiration Index （SPEI） to analyze the frequency and characteristics of extreme drought events in Southwest China from 2001 to 2016.We focused on the 2009 -2010 extreme drought event， which had the longest duration and the widest spatial impact.The Community Land Model version 5 （CLM5.0） was employed to numerically simulate vegetation growth during this extreme drought event.The applicability of the CLM5.0 model for assessing vegetation responses to drought in Southwest China was validated by comparing the simulation results with three remote sensing datasets （GLASS， GIMMS， and GLOBMAP）.Our results revealed that between 2001 and 2016， there were three extreme drought events lasting more than six months in Southwest China， with the most prolonged and severe event occurring in 2009 -2010.The CLM5.0 simulation indicated that during 2009 -2010 extreme drought， CLM5.0 effectively captured the correlation between vegetation and drought， including lagged responses， cumulative effects， as well as resistance and resilience.The intensity of vegetation response to drought decreased from southeast to northwest， with 68.66% of regional vegetation exhibiting a lagged response.Moreover， the lagged response （78.02%） and cumulative effect （89.17%） showed large-area positive correlations with drought， which were consistent with observations from multi-source remote sensing.In terms of simulating the resistance and resilience of different vegetation types to drought， CLM5.0 performed reasonably.Forests exhibited stronger drought resistance compared to shrubs and grasslands， and forests displayed an inverse trend in resistance and resilience.The validation of CLM5.0 model simulations with multi-source remote sensing validation in this study offers a complementary perspective for understanding the multifaceted responses of vegetation to drought in Southwest China， contributing to a more comprehensive assessment and prediction of the impacts of drought on vegetation activities in the region.