Abstract：Based on the background of rising temperature, changes in precipitation and its pattern, and increased vegetation coverage and biomass, the changes in global water resources have attracted widespread attention and concern. We analyzed the long-term data of runoff, normalized differential vegetation index(NDVI), mean annual temperature(MAT) and annual precipitation(AP) in 2894 watersheds around the world. The results suggest that on regional (continental and latitude belts) and global scales, LQ decline and HQ rise are not found, and the down-trends in MQ is linked to the down-trends in HQ, and the up-trends in MQ is linked to the up-trends in LQ. Indicating that global water resources and distribution of precipitation over a year have improved over the past 60 years on the regional and global scales. Further analysis pointed out that climate change is the main factor leading to changes in water resources and distribution within a year. However, unlike the changes in the monthly extreme discharge (LQ or HQ), the months in which the extreme monthly discharge occurs have undergone significant changes. This change may have a profound impact on society and natural ecosystems, as well as production and lifestyles that rely on natural rhythms.