Abstract: Geothermal water in Tibet has a high degree of mineralization with abundant mineral substances. Simultaneous determination of potassium, sodium, calcium, magnesium, silicon, boron, lithium, strontium, arsenic, iron and sulfate radical in geothermal water of Riduo Hotspring by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) was developed in this study. Analytical conditions were optimized by application of two-way observation mode to ensure simultaneous determination of the multi-elements in geothermal water. In addition, geothermal water was preserved in 1% nitric acid and the results of 11 elements after five weeks are stable. This method has a detection limit of 0.0006-0.0162 mg/L, recoveries of 95.5%-105.8% by standard addition, and relative standard deviation (RSD, n=10) of less than 6%. The analytical results were in good agreement with those obtained by traditional methods. This method provides a number of reliable data for hydrogeochemical research on geothermal water in Tibet.