The variation tendency of river runoff,precipitation and temperature over drainage areas of the major rivers in Qinghai province was analysed by using nearly 38 years observative data.The Influence of dry climate on the surface water resource in Qinghai was mainly discussed.The results show that the inland rivers are mainly supplied by mountain snowmelt and precipitation,and the outflow rivers are mainly supplied by precipitation.The surface water resource in Qinghai tends to decrease and the tendency is more obvious after the 1990s.The temperature and precipitation are primary influent factors on the surface water resource of Qinghai province.Temperature increasing causes evaporation enhancement,drought aggravation and surface runoff reduction.Precipition decrease after the 1990s,especially during flood season,and it leads to a direct reduction of surface runoff.