Oinghai Lake is located in the northeastern part of Qinghai—Xizang(Tibet) Plateau,and it is a typical continental brackish-water lake.The lake water belongs to sodium sulphate subtype with a salinity of 14.07 g/l。and obviously difers from seaw ater in chem ical com position.It is satum ted by CaC03 and aragoniteis se parating out.In order to reveal the evolving tendency of the lake water,salt—separating sequences an d forming conditions of various salt deposits,we took a large amount of lake —water near the southem bank of the lake and carried out the evaporating and freezing—evapo rating experim ents.The evapo rating experim ental results show that,hydrom agnesite is first se parated with the lake—water being concentrated,and then halite,the nardite,bloedite,picrom erite,epsom ite,syM te and cam allite precipitated uccessively.The resuhs of freezing evapora tion show that,first hydrom agnesite,and thenmirabilite,nesquchonite,halite,epsom ite,camallite and bischd ite se parated,respectively.The final m oth er liquid of those experim ents were preserved for1—2 months(in laboratory) and borates were precipita ted.The above salt—se parating equence and crystallization pathway bviously difer from those of seawater,and ale sim ilar to some saline lakes on Qinghai—X izang(Tibet)Plateau and sOrlle an cient lak e basins fTertiary in the eastern China,such as Dalongtan Playa(Qaidam Ba— sin)and Dawenkou Basin(Shandong province) etc..Therefore these experimental results ale very important for illustrating the evolving tendency of the Qing hai—Lake water and the formation and evolution of the salt lakes of Oinghai—Xizang (Tibet) Plateau,as well as the form ation of potas hdeposits and other salt resources in conti-nental lake basins.