To better understand the source changes and the response of river water to climate change, waters in mainstream and tributaries in Yellow River Basin were sampled from July to August 2012, and temporal and spatial variations of hydrogen and oxygen isotope values in water samples were analyzed. The results showed that (1) Excluding source water, the values for hydrogen, oxygen isotope, and d excess in mainstream waters in Yellow River ranged from -97.2 to -62.9 with mean value of -72.2, and from -13.0 to -8.7 with mean value of -9.9, and from 4.1 to 11.0 with mean value of 7.0, respectively. For tributary water, the values for hydrogen and oxygen isotope varied from -103.8 to -30.5 with mean value of -68.9 and from -13.7 to -1.5 with mean value of -9.2, respectively, and the d excess varied between -18.5 and 13.2 with mean value of 4.5; (2) The hydrogen and oxygen isotope values in water from the upper-stream of Lanzhou station and middle-stream of Yellow river were more negative than those of water from upper-stream between Lanzhou station and Toudaoguai station and the low-stream, while the d excess values decreased gradually along the flow path; (3) The Na~+/Cl~- molar ratios varied from 0.94 to 3.02. The mean value of Na~+/Cl~- molar ratio was 1.02 in source water, and 1.58 in mainstream water above Lanzhou station, and 1.30 in mainstream water between Lanzhou station and Toudaoguai station, and 1.79 in middle-stream water and 1.41 in low-stream water. The negative correlation between Na~+/Cl~- molar ratio and oxygen isotope values of river water indicated that the Yellow River waters were mainly controlled by atmospheric deposition, groundwater recharge and evaporation; (4) Compared with results of previous studies, it was found that since 2000, the annual water flux of Yellow River increased gradually, the second-evaporation effect on the upper-stream river water decreased, and the evaporation effect on middle and low stream water also decreased, indicating that the climate in Yellow River Basin was becoming less dry.