Lake Fuxian(24°21'13"~24°37'57"N,102°49'14"~102°57'33"E) is one of the deepest inland large lakes in China.In this paper,the carbonate contents,calcite mineral compositions by XRD and element Ca by XRF on the core FXH-B2 drilling from southern center of the lake was analyzed,.The studied core FXH-B2,located at 24°24'57.48"N,102°52'06.24"E is 296 cm long.Combing with the chronology established by 9 ~(14)C dates using AMS ~(14)C dating method,stable isotope analyses on carbonate and organic matters and geophysical data,the contents of carbonate and calcite minerals and element Ca,and their relationships,the significances to reveal water level fluctuations were discussed.Based on these discussions,the water level change history of Lake Fuxian since the last ca.12 ka was reconstructed.It was calculated that the studied core had a sedimentation rate of 0.24 mm/a.The analysis results show that there is a high correlation between carbonate content and the XRD signal strength of calcite (R~2 = 0.87) and XRF scanning data of sediment Ca elements (R~2 = 0.85).The carbonate in the sediments of Lake Fuxian are composed of mainly calcite (the relative content of other carbonate minerals is low or even negligible).The high correlations between carbonate contents,the calcite contents and the relative content of Ca element indicate that in Fuxian Lake sedimentation the Ca element mainly come from calcite.Therefore,their contents were determined by the content of carbonate.Changes in carbonate content in sediments can be expressed by the results of XRF results of Ca elements in sediments.Because Lake Fuxian is located in the subtropical monsoon climate zone,dry and wet oscillations of the climate control the main process of lake evolution process,the lake sedimentary proxies,such as the Ca element,and or carbonate and calcite contents mainly reveal the water level change history in the past.Based on this assumption,the reconstructed lake water level changes during last 12 ka demonstrates a gradual decrease 12.04 cal.ka B.P.to 2.20 cal.ka B.P.During this processes,the high CaCO_3 content,more positive delta~(18)O and delta~(13)C values reveal a lowest lake water level period between 4.37 ~2.20 cal.ka B.P.,during this period the water level decreased by ca.30 m,indicating a driest event since 12 ka B.P.This water level decrease is further conformed by the geophysical measurement results in the northeastern of the lake where the underwater human relics was found and the subwater landscape measured erosion features.An abrupt water level rising occurred between 2.2 ~ 2.0 cal.ka B.P.and reached the level almost continuous to the present.This abrupt raise of the water level might influence the human activities in the area that need further study.