There are many salt lakes on the QinghaiTibet Plateau, China. Carbonatetype salt lakes such as Zabuye Salt Lake and magnesium sulfatesubtype salt lakes such as Dong Taijnar Lake are famous Lirich salt lakes and have been exploited successfully and produced lithium carbonate. There are also many salt lakes of sodium sulfate subtype on the QinghaiTibet Plateau, and brines in these salt lakes have a high concentration of lithium in addition to other abundant useful components such as potassium, boron and magnesium. No research has been made on exploitation and utilization of these salt lake resources so far. In this paper, the kinetic model of the system Li+, Na+, K+, Mg2+/Cl-, SO2-4H2O constructed using Pitzer’s electrolyte solution theory is used to conduct computer simulation of isothermal evaporation of several kinds of Lirich brine of sodium sulfate subtype at 25 ℃. The authors predicted the sequence of precipitation of minerals during the evaporation, change in brine composition, saturation points of sodium, potassium, magnesium and lithium salts, and on that basis they made theoretical calculations of the balance relationships of materials during the evaporation of brines. The simulation involves three kinds of brines of sodium sulfatesubtype in Tibet and two kinds of brines of sodium sulfatesubtype. The simulation results of Silver Peak brines in the United States are in complete agreement with those of the evaporation process of the experiment. The results of simulation of Lirich brines can be used as theoretical reference for the design of the technological line of comprehensive exploitation and utilization of this type of brine resources.