Abstract: The runoff variations were analysed by a correlation method of preci-pitation runoff and precipitation and a method of ice-melt water modulus. The results show that the total runoff, ice-melt water and precipitation runoffs had reducod by about 14.8%,39.9% and 14.3% respectively, since Little Ice Age in the Daxisou-Urumqi River.It is inferred that the surface runoff in the Daaigou will continue decrease with a rise of air temperature in the future,and the surface runoff will reduce much more as compared with the precipitation.