The study analyzed the characteristics of runoff in the upper Wuyuerhe River Basin from 1956 to 2006. The researchers found that the annual runoff was uneven, mainly in July and August, with significant differences between wet and dry years. There were clear stages of annual runoff changes, showing a significant reduction trend. The main period of annual runoff changes was around 41 years, with a sudden decrease in 1964. The decrease in precipitation and human activities were identified as key factors affecting the runoff.