Abstract: According to climatic information,¹⁴C dating,spore-pollen analysis and grain size data of Halali loess profile,and the distribution and ¹⁴C dating of depositional terrace at south bank of Qinghai Lake,the paper discusses the climatic changes in Qinghai Lake area and the Lake level fluctuations since 10300 years B.P.It is pointed out that there are four relatively warm and humid periods in Qinghal Lake area since the Holocene.They are the periods from 10300 years B.P.to 8500 years B.P.,from 7000 years B.P.to 3500 years B.P.,from 2800 years B.P.to 2000 years B.P.,and from 3500 years B.P.to present time.The optimum climate period in Qinghai Lake area was the period from 7000 years B.P.to 3500 years B.P.when polypodium plants grew luxuriantly around Qinghai Lake,it was quite warm and humid,the average annual temperature was 2.5℃ higher than that at present.The cold and dry periods happerned in 8500 years B.P.to 7000 yearsB.P.,3500 years B.P.to 2800 years B.P.and 2000 years B.P.to about 1300 years B.P..Qinghai Lake level generally tended to lower in the Holocene,but there were four periods of relatively stable high lake-level corresponding to warm and humid periods.