Abstract: Based on the study of hydrogen stable isotope between the high and low altitude watershed in the Heishui valley of the upper Minjiang River, δ D was found to be positive in spring and negative in summer, and show a positive tendency with decreasing of altitude. The results also showed that the spatial and temporal variation of hydrogen stable isotope in the river water reflected the interaction between mechanism of precipitation formation and the terrain patterns. The contributions of different water sources changed in the different periods. During the high-flow period, either in the high ahitude watershed or in the low altitude watershed, contributions of the rainfall to the river water were always more than 20~.