In recent years, a growing number of reports and studies have shown that extreme weather events will become more frequent, which will cause serious impacts and losses to society, economy and human life. In the context of global warming, it is especially significant to explore the characteristics of extreme climate change and its impact on ecosystem. Vegetation plays a key role in the terrestrial ecosystem. The Normalized Difference Vegetation Index (NDVI) is the best indicator for monitoring the growth state and spatial distribution of terrestrial vegetation, and is often used to reflect the response of vegetation dynamics to climate change in the region. The Inner Mongolia is located in a fragile ecological environment and is particularly sensitive to climate change. Therefore, it is necessary to explore the dynamic change of extreme climate in Inner Mongolia and its impact on vegetation, which can provide a scientific basis for disaster mitigation and ecological restoration projects in the Inner Mongolia. Based on the daily meteorological data of 115 meteorological stations in the Inner Mongolia from 1982 to 2020, this paper selected and calculated 18 extreme climate indices from three dimensions of intensity, duration, and frequency, and comprehensively analyzed the temporal and spatial variation characteristics of extreme climate. On this basis, the geographical detectors and Pearson correlation analysis methods were used to quantitatively evaluate the impact of extreme climate on vegetation in the region. The results showed that:(1) the extreme warm temperature indices all showed an increasing trend, indicating that extreme warm phenomenon in the Inner Mongolia has increased during the period 1982-2020. (2) Both consecutive dry days and consecutive wet days showed a decreasing trend, indicating that the continuous drought and precipitation events in the Inner Mongolia have decreased in the past 39 years. (3) The correlation between the extreme climate indices and the NDVI showed obviously spatial heterogeneity, which is shown as follows:the NDVI and extreme warm indices are positively correlated in the east, but negatively correlated in the central region; the NDVI was significantly positively correlated with extreme precipitation intensity and frequency indices in the central Inner Mongolia. (4) The factor detector results showed that the extreme precipitation index had a greater impact on the vegetation growth and changes than the extreme temperature index in the Inner Mongolia. In general, the paper can provide the theoretical evidence for disaster mitigation and ecological environment conservation in the Inner Mongolia.