Abstract: The mineralization extent of thermomineral water in Tibet is relatively high, together with high altitude and low air pressure, resulting in the differences in the working conditions of Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) between Tibet and low altitude areas. Therefore, the measuring method in low altitude areas cannot be used in Tibet. By optimizing the working conditions of the instrument, adding internal standard, and establishing an interference correction equation, the influences of low pressure and hyper-salinity are eliminated. Simultaneous determination of 12 trace elements in thermomineral water by ICP-MS was developed in this study. At the same time, the radioactive element uranium in thermomineral water was also detected. Correlative factors of the calibration curve were all above 0.9995. The detection limits of this method were 0.012-0.128 μg/L, the relative standard deviations were 1.2%-6.8%, and the recoveries of spiked samples were 95.7%-106.5%. Combining with previous findings of this program, ICP-MS is more suitable for measuring trace elements in thermomineral water of hyper-salinity, while ICP-OES is suitable for the determination of major elements. The combination of these two methods can form a system of analytical techniques of thermomineral water in high altitude areas.