Vegatation NPP is considered to be a key factor of ecological responses to climate change. The objective of this study was to analyze the spatial- temporal variations and hydrological effects in the source region of the Yangtze River. Trend analysis, correlation analysis and runoff process indexes were applied based on MODIS NPP products over the period of 2000-2010, as well as annual runoff, temperature and precipitation data in the same period. The results indicated that during the period 2000- 2010, the annual NPP (aNPP) of vegetation tended to increase at a rate of 48.22 gC/m~2. Influenced by water and heat resources, vegetation aNPP increased from northwest to southeast, which showed an obvious spatial heterogeneity. Moreover, the increase rate of different vegetation types varied across the study region. The aNPP of coniferous forest increased fastest among all vegetation types with a rate of 3.03 gC/(m~2? a), followed by shrub, alpine meadow and alpine grass, the rates of which were 2.68, 1.43 and 0.85 gC/(m~2 ? a), respectively. The increase of vegetation NPP was distinctively related to temperature from June to September and precipitation from May to August, which showed a significant positive correlation. The increases of runoff coefficient and water conservation index during the period 2000-2010 were also shown in the increase of vegetation aNPP, which was advantageous to water resources in the source region of the Yangtze River.