The Maotiaohe River is the first river in China which has been completely developed for hydropower in a cascade manner.In this study,we systematically analyzed the regimes of hydrometeorological variables and detected their possible trends.Meteorological and hydrological observations on a daily basis were obtained at three weather stations in the vicinity of the Maotiaohe Basin for the period of the 1950-2010.Linear regression and the Mann-Kendall non-parametric trend detection technique were applied.In addition,daily reference crop evapotranspiration was calculated based on the FAO56 equation.The results showed that the mean annual precipitation ranged 1 000-1 300 mm/a in the watershed,while no statistically significant temporal trend was detected.The temperature of the watershed increased about 0.4-1.0 ℃ over the past 60 years,exhibiting a warming trend.The mean annul sunshine hour ranged 1 200-1 300 h/a,showing a decreasing trend at a rate of 8-10 h/a.Daily crop evapotranspiration was found to be 2.5-2.7 mm/d and mean annual reference crop evapotranspiration ranged 900-1 000 mm/a over the study period,displaying a decreasing trend over time.The decrease of evaportranspiration was closely correlated with the trend in sunshine hour.Overall,the Maotiaohe River watershed showed a slightly warming trend,which did however have not resulted in a significant impact yet on water resources of this watershed.