Abstract: In recent years, extreme climate events have occurred frequently in China. Studying the laws of extreme climate change can prevent the harm caused by natural disasters to human life and the imbalance of water resources distribution. The Yalong River has important hydropower energy in China. Based on the daily rainfall and temperature data of Yalong River Basin from 1961 to 2018, 26 extreme climate indexes are calculated, and the trend and mutation of extreme climate indexes are analyzed by linear fitting, Sen’s slope estimation, Mann Kendall Catastrophe Test and Pettitt Test. The inverse distance weighted spatial interpolation method（IDW） is used for spatial interpolation to analyze the spatial distribution characteristics of extreme climate indexes. The results show that the extreme high temperature, low temperature and average temperature difference index in the Yalong River Basin are high in the south and low in the north; The temperature in the north of the basin is cold, and the number of freezing and frost days is long, while the temperature in the south is warm, and the number of summer days and the length of growth period are long. In addition to the continuous dry period, the extreme precipitation index is also high in the south and low in the north in space, and reaches the maximum in the southeast. Under the trend of global warming, the maximum and minimum temperature extremes rise, and the high-temperature growth rate is less than the low-temperature growth rate, so that the temperature difference gradually decreases. The number of freezing and frost days decreases, the number of summer days, the length of growth period and the duration of warm days increase, making winter shorter and summer longer in the basin, and the temperature duration suitable for animal and plant growth increases. Except for the continuous dry period, the extreme precipitation index shows an upward trend. The annual precipitation increases the most, followed by heavy precipitation. It indicates that from 1961 to 2018, the extreme temperature in the Yalong River Basin tended to be warmer, the number of warm days in the year increased, the extreme precipitation increased as a whole, the precipitation and precipitation intensity increased, and the precipitation duration lengthened. It is also necessary to prevent the increase in extreme precipitation in the Yalong River Basin. The study of the space-time change law of extreme climate in Yalong River Basin provides a scientific basis for the development and management of water resources and disaster warning in the basin.