An analysis was made of observed data around the Qinghai Lake from 1961 to 2000, and the results show that the climatic tendencies of the annual and seasonal air temperature and surface evaporation and summer and winter precipitation change were all positive, while the climatic tendencies of spring and autumn precipitation change were negative. The tendencies of temperature rising and surface evaporation increasing were more significant, while the tendency of precipitation increasing was less obvious and its inter-annual change was slightly greater. The meteorological factors such as air temperature and surface evaporation shows the tendency of transiting toward warm and dry, which is the main cause of the falling water level of the Qinghai Lake.