Combined with the climate tendency analysis and wavelet coherence analysis, the daily precipitation and temperature data from 1971 to 2017 were used to reveal the spatiotemporal variations of extreme precipitation in the Three River Source Area of the Shaanxi-Gansu-Ningxia Contiguous Region and explore the relationship between extreme precipitation and the El Niñ o-Southern Oscillation(ENSO)activities. The results show that there was a significant increase in extreme precipitation in the Three River Source Area from 1971 to 2017. Precipitation in this region has an apparent spatial pattern with higher values in the south and lower values in the north, showing the apparent impacts of geography and topography. Changes in the extreme precipitation indices in this area are mixed. In most areas, the amount of extreme precipitation, number of heavy precipitation days, and precipitation intensity increase over the study period, while the number of low precipitation days decreases over time, indicating that precipitation in this region tends to become more extreme. There were significant negative correlations between the extreme precipitation indices and the multivariate ENSO index(MEI), and the periods of maximum coherences between extreme precipitation indices and MEI are 3-5 a and 9-12 a.