Abstract: On the basis of analysis of the variations of temperature and precipitation in the Yellow River Source Region, the evapotranspiration was calculated by Turc experiential model and the soil humidity and net primary productivity aboveground in the last ten years were analyzed. The results suggested that temperature and evapotranspiration were significantly correlated and increased by 0.0284℃ per year and 0.7315mm per year respectively, while the precipitation was stable in 1959-2005. This drier and warmer tendency could be proved by the soil moisture monitoring results since 1987. The net plant primary productivity aboveground decreased by 9.506 g m-2 per year as meteorological factors changed.

Key words: Yellow River source regions, Yellow River source regions, Climate change, Evapotranspiration, Ecosystem