Abstract: The compositions and sources of carbonates and their relation to the physical and chemical characteristics of lake waters for Qinghai Lake were studied；the relationship between the saturation index of aragonite and temperature， Mg/Ca ratio was established； and the paleoclimatic evolution of Qinghai Lake since 16 ka B．P．was discussed．The results indicate that the carbonates in the sediments of Qinghai Lake are mostly authigenetic and are mainly composed of aragonite since 16 ka B．P．．The stage of high aragonite content reflects warm-humid climate，while that of low aragonite content reflects the cold．dry climate． The Paleoclimate and Paleoenvironment of Qinghai Lake since 16 ka B．P．recorded by carbonates are as follows：The boundary betwen the Last Glacial and the Lateglacial is at 15.2 ka B．P．．During the Lateglacial，the climate fluctuated frequently，but with small amplitude．There cold events in the periods of 13.4～ 13 ka B．P．．11.6～ 12 ka B．P．an d 11～ 10.4 ka B．P．correspond to the Oldest Dryas， Older Dryas and Younger Dryas event， respectively， whereas the two warm periods between them ，12～ 13 ka B．P．and 11.6～ 11 ka B．P．, correspond to Bo11ing and Allerod period ，respectively．During the early stage of the Holocene (from 10.4 ka B．P．to 10ka B．P．)，the aragonite disappeared and much dolomite emerged ，which may be related to more fresh water flowage into the saline lake．This indicates that the temperature an d rainfall increased abruptly in the early Holocene．The Holocene warm climatic optimum culminated at 6.7 ka B．P．when the salinity of lake water was lower．The climate fluctuated fast as it turned from warm to cold and from hum id to dry between 6.7 ka B．P．and 4 ka B．P．．The climate tended to be cold and dry since 4 ka B．P．． Qinghai Lake