Abstract: Based on satellite remote sensing data from 2005 to 2020 and long-term ozone sounding data from multiple global stations, this study quantitatively assesses the contribution of tropospheric ozone to the total ozone column. The results show that the annual average tropospheric ozone accounts for approximately 9%–13% of the total column ozone, with significant spatial and seasonal variations. Spatially, the tropospheric ozone proportion increases from the equator toward the mid-latitudes, then decreases toward the high latitudes, with the highest values (12%–13%) in the mid-latitudes and the lowest (9%–10%) in the equatorial and polar regions. The Northern Hemisphere shows a higher tropospheric ozone fraction than the Southern Hemisphere. The tropospheric ozone proportion peaks in summer, with the highest values extending poleward, whereas in winter they shift toward the equator. Over the Qinghai–Xizang Plateau, the proportion of tropospheric ozone is influenced by multiple factors, including high surface elevation and the seasonal variations in the tropopause height. Compared to other regions at the same latitude, the Plateau exhibits a lower average tropospheric ozone fraction, by approximately 1.82%–2.74%. Furthermore, the tropospheric ozone proportion over the Qinghai–Xizang Plateau shows a distinct spatial pattern, with higher values in the north and lower values in the south, and marked seasonal differences, reaching a maximum in summer (12.24%) and a minimum in winter (8.67%).