2009年9月至2010年3月我国西南地区出现了有气象记录以来最严重的干旱,给当地的自然环境和生产、生活带来严重影响。本文利用多年MODIS/EVI数据求取距平植被指数来反映干旱对西南地区植被的影响。在此基础上,分析了西南地区植被受旱的时空格局及其可能影响因素。结果表明,我国西南地区植被受干旱影响的范围很大,超过地区总面积的50%,植被受旱程度时空差异显著。这种显著的差异除了受降水等气象因素影响外,还与不同植被类型对干旱的响应差异有很大关系。在西南地区三种主要的植被类型中,作物是最易受干旱影响的植被类型,草地次之,林地的抗旱能力最强。此外,植被干旱的空间分布与气象干旱也存在很大的差异,进一步证明了降水以外的其他因素对干旱程度的调节作用。研究证明与气象干旱指数相比,植被指数更能反映干旱的实际情况。但在使用植被指数衡量干旱影响时也要考虑到植被指数本身的局限性。 From September 2009 to March 2010, the worst drought in meteorological records in southwestern China occurred, which seriously affected the local natural environment and production and life. In this paper, the use of MODIS / EVI data for years to obtain the anomaly vegetation index to reflect the impact of drought on the southwestern vegetation. On this basis, the spatio-temporal patterns of vegetation drought in Southwest China and its possible influencing factors were analyzed. The results show that the vegetation in Southwest China is affected by the drought in a wide range, exceeding 50% of the total area of ​​the region. The spatial and temporal difference of the degree of drought in the vegetation is significant. In addition to precipitation and other meteorological factors, this significant difference is also closely related to the differences in response to different types of vegetation. Among the three main types of vegetation in Southwest China, crops are the most vulnerable types of vegetation, followed by grasslands, with the strongest drought resistance in woodlands. In addition, there is a great difference between the spatial distribution of vegetation droughts and meteorological drought, which further proves that the regulation of the degree of drought on other factors than precipitation. Research shows that compared with the meteorological drought index, the vegetation index can better reflect the actual situation of drought. However, the use of vegetation indices to measure the effects of drought also takes into account the limitations of the vegetation index itself.