Abstract: The southern Himalayas is rich in geothermal resources. The study of the formation mechanism of geothermal water and travertine is helpful to understand the characteristics of geothermal resources and the information of paleoclimate change. It is of great theoretical significance to enrich the systematic study of geothermal resources in Shannan and the study of climatic and environmental changes in Qinghai-Xizang Plateau. In this study, three hot springs in Qiongduojiang, Gudui and Quzhuomu in Shannan area of eastern Himalayas are taken as the research objects. By collecting the data of hot spring geothermal water and travertine, the characteristics of geothermal water-rock interaction, the estimation of geothermal reservoir temperature of geothermal water, the traceability of geothermal water supply source, the genetic type and formation age of hot spring travertine and the climatic significance of travertine are comprehensively analyzed. The results show that the hydrochemical type of Qiongduojiang hot spring is HCO₃·Cl-Na·Ca type; The hydrochemical type of Guduiriruo boiling spring is HCO₃·SO₄-Ca·Na type. The hydrochemical type of Guduichaka boiling spring is Cl-Na type; The hydrochemical type of Quzhuomu hot spring is Cl·SO₄-Na·Ca. The source of anions and cations in hot spring geothermal water is mainly the dissolution of silicate rocks and the dissolution of some carbonate rocks and salt rocks. Since the hot spring geothermal water has not reached the water-rock equilibrium state, the shallow thermal reservoir temperature is 129～148°C by using the quartz geothermal temperature scale, and the deep thermal reservoir temperature and cold water mixing ratio are 181～221°C and 58%～65% by using the silicon-enthalpy diagram. Hydrogen and oxygen isotopes show that the geothermal water supply elevation is 4467～5303 m. In Shannan area, geothermal water is recharged by high-altitude atmospheric precipitation and ice and snow melt water. It migrates to the deep through the main fault structure to heat and rises along the fissures and joints under high temperature and high pressure. Then it is mixed with shallow cold water, and finally exposed along the shallow surface loose fracture zone to form a hot spring. Hot spring travertine CaO accounts for 43.43%～56.66%, and shows the characteristics of light rare earth element enrichment; the δ¹³C indicates that the hot spring travertine is thermogenic, and the carbon in travertine is mainly derived from the metamorphic origin of deep carbonate rocks, and only part of mantle carbon is found in Guduiriruo boiling spring; ¹⁴C dating shows that the age of travertine is 21280±70~>43500 years, the ratios of Mg/Ca and Mg/Sr indicate that the rainfall decreased rapidly from the peak in 43.50 ka, and gradually increased from 42 ka to 21.28 ka.