[Objective] Correlations among precipitation, soil water and river water were analyzed in Dayekou Basin of Qilian Mountains in order to explore the ecological and hydrological processes of basin and river runoff formation. [Methods] More than 380 thousand data observed artificially for 18 years and obtained automatically for 2 years were processed using methods of characteristic-parameters algorithm, correlation analysis and multiple regression. [Results] (1) The annual precipitation, air humidity and river runoff depth averaged over the 18 years' artificial observations were 374.06 mm, 60.91% and 166.73 mm, respectively. The river runoff accounted annually for 44.57% of the precipitation. The precipitation, air humidity and river runoff all showed rising trends with average rates of 18 mm/10 a, 1.12%/10 a and 18 mm/10 a, respectively. (2) The precipitation, air humidity, soil moisture and river runoff varied intra-annually in step. (3) With the height increase from forest ground, the influence of precipitation on air humidity decreased; In 0-80 cm soil profile, with the increase of soil depth, the influence of precipitation on soil moisture also decreased . (4) The relationship between rainfall, air humidity, soil water, river water more closely, the regression model among precipitation, air humidity, soil moisture and river runoff can interpreted the 95.2% and 88.8% and 97.6% variances of precipitation, soil moisture and river runoff, respectively, and with averaged prediction accuracies of 93.4%, 84.6% and 96.7%. [Conclusion] The proportional allocation among precipitation, soil water, river water could be quantified and regulated. The data acquiring methods of manual observation and automatic monitoring could well solve the ecological and hydrological processes research in river basin.