In order to effectively grasp the change characteristics and evolutionary trends of runoff in the Datong river basin and provide accurate services for water resource management, this article used the measured runoff data from watershed control stations, and adopts the non-uniform coefficient analysis method, complete adjustment coefficient method, univariate linear regression method, 5-year moving average method, and Maan Kendall non parametric test method to analyze the annual distribution characteristics of runoff. The study was conducted from multiple perspectives of annual distribution, interannual variation, variation years, and evolution trends of watershed runoff. The results showed that the annual distribution of runoff was extremely uneven, with significant differences in extreme values.Runoff was mainly concentrated in July, August, and September. With the extension of the year, the annual distribution becomed more uniform and the degree of concentration becomed weaker. The interannual variation was relatively stable,showing a significant decreasing trend. In the past 67 years, the runoff decreased by 408 million m?, with a decrease rate of 0.068 million m?/a. Water transfer crossing basins was the main reason for the decrease in runoff. The runoff varied in 1961, 2003, and 2010. The study can provide reference basis for rational allocation of water resources in river basins, river and lake management, and water use for industrial and agricultural production.