Based on the runoff data measured by Gadatan hydrological station and Xiangtang hydrological station in the Datong River Basin from 1952 to 2014, the distribution of runoff during the year was analyzed using unevenness, the mutation and periodicity of runoff in the basin were analyzed respectively by Mann-Kendall nonparametric test method and Morlet wavelet transform method. The results show that The flood season of the Datong River Basin was mainly from May to October, with a runoff proportion of 87.81% in Gadatan hydrological station and 81.9% in Xiangtang hydrological station. The upstream area presented a more uneven coefficient and a higher concentration rate than the downstream area. Before 1991, the runoff changes in the upper and lower reaches of the Datong River both showed a downward trend. After 1994, the flow of the Gadatan station showed a slight increase trend, and the runoff at the Xiangtang Station still showed a rapid downward trend. There are periodic oscillations around 4a, 8a, 21a in the Gadatan station, with 3a, 6a, and 31a occurred in the Xiangtang station. Before 1994, runoff was mainly affected by temperature and precipitation. After 1994, it was mainly affected by human activities.