Global Positioning System Radio Occultation (GPS RO) measurements is particularly suitable for the study of tropopause characteristics due to the high measurement accuracy at the tropopause height. COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) occultation data from 2007 to 2013 were used to calculate the tropopause heights over the Tibetan Plateau according to the WMO (1957) tropospheric height discriminant method, and radiosonde data were used to verify the results. The height characteristics of the troposphere over the Tibetan Plateau, and the distribution of water vapor in the troposphere were analyzed. The results showed that there was a high linear correlation between the tropopause heights detected by COSMIC occultation data and radiosonde data over the Tibetan Plateau. The correlation coefficient was as high as 0.976, the average deviation was 0.448 km, and the root mean square error was 0.672 km. Influenced by thermodynamic factors, the tropopause over Tibet Plateau is highest in summer and lowest in winter and spring. From winter to summer, the position of the tropopause break area gradually moves northward. In spring, winter and autumn, affected by the equatorial heat source, the entropy surface from low to high latitude rises, with the water vapor mixing ratio decreasing gradually in the middle and lower troposphere. In summer, under the effect of the deep convection caused by the heat source and the horizontal transport caused by the monsoon, a high value area of water vapor appears above the Qinghai-Tibet Plateau.