Abstract: In this paper,the temporal changes of climatic factors were analyzed using the daily meteorological data from 13 stations in the headwaters of the Yellow River Basin during the period from 1959 to 2008.The regional climate change was researched using the precipitation and evapotranspiration ratios estimated with the FAO Penman-Monteith model.The results are as follows:(1) Climate became obviously drier and warmer in the southeast part but wetter and warmer in other parts of the study area during the period of 1959-2008.The warming trend was dominant; (2) Average annual and minimum temperature was mainly in an increase trend during the periods of 1959-1988,1969-1998 and 1979-2008.The increase trend of maximum temperature occurred in recent 30 years; (3) Under the effects of increase of minimum and maximum temperature,the increase trend of average annual temperature was the most obvious during the period of 1979-2008; (4) Sunshine duration was in a significant decrease trend at the meteorological stations with lower elevation,and it was in an obvious increase trend at the Maduo and Dari stations with higher elevation; (5) Increasing trend of relative humidity was dominant at the stations with lower elevation,but the relative humidity was in a decrease trend at most stations with higher elevation; ⑥ Wind speed was in a decrease trend,especially at the stations with lower elevation and during the latter two periods.Thirty-year time interval was feasible for analyzing climate change.

Key words: climate change, temperature, precipitation, sunshine duration, relative humidity, wind speed, dry and wet climate boundary, headwaters of the Yellow River Basin