Global warming has intensified regional climate change and increased the frequency of extreme climate events, altering watershed hydrological processes and further amplifying runoff uncertainty. Understanding the relationship between extreme climate events and runoff changes over long timescales is of great significance, particularly for ecologically fragile semi-arid regions. This study, based on high-resolution climate and runoff observational data from 1963 to 2020, employs methods such as the Mann-Kendall（MK）test, Pettitt test, and wavelet analysis to explore the characteristics of extreme climate change and its impact on hydrological drought in the Xilin River Basin. The results show that:（1）Precipitation exhibits a decreasing trend of ?0.2mm/10a, while temperature and potential evapotranspiration significantly increase at rates of 0.4°C/10a and 8.2mm/10a, respectively.（2）The standardized runoff index（SRI）significantly decreases at a rate of ?0.2/10a, with a noticeable change point in 2001, indicating an intensified hydrological drought trend.（3）The intensity and frequency of extreme temperature indices have significantly increased. The climatic trends for the monthly maximum temperature（TXx）, annual maximum daily minimum temperature（TNx）, summer days（SU）, and hot nights（TR）are 0.4°C/10a, 0.5°C/10a, 4.4 d/10a, and 1.0 d/10a, respectively. In contrast, the extreme precipitation indices show insignificant decreasing trends. The climatic trends for heavy precipitation total（R95pTOT）, simple daily precipitation intensity（SDII）, consecutive wet days（CWD）, and the number of heavy precipitation days（R10mm）are ?0.2mm/10a, ?0.1mm/10a, ?0.2d/10a, and ?0.1d/10a, respectively.（4）The SRI is positively correlated with precipitation and the intensity and frequency of extreme precipitation, and negatively correlated with temperature, potential evapotranspiration, and the intensity and frequency of extreme temperature events.（5）Significant resonance periods of 6—10a exist between SRI and precipitation, temperature, and potential evapotranspiration, while the significant resonance period with extreme climate events is 2—3a. The study found that climate change in the Xilin River Basin is characterized by a trend of warming and aridification. Extreme temperature events have significantly increased, while extreme precipitation events have not shown a corresponding rise, which has led to an exacerbation of hydrological drought risks. Among the various factors influencing this trend, precipitation and the R10mm index, which represents the number of days with heavy precipitation, are key drivers of runoff variability. The findings of this research provide valuable insights that can aid in the management of watershed water resources in arid and semi-arid regions, particularly under the influence of extreme climatic events. These results can inform strategies for coping with the challenges posed by the changing climate in such vulnerable areas.