Based on two ozone concentration data sets from the European Center for Medium-Range Weather Forecasts （ECMWF） 43a （from 1979 to 2021） and the National Aeronautics and Space Administration （NASA） 42a （from 1980 to 2021）， combined with high pressure， mean sea surface temperature， and circulation field data from South Asia， this study examines the spatial and temporal distribution of ozone in the Upper Troposphere and Lower Stratosphere （UTLS） over the Qinghai-Xizang Plateau （QXP）.The study found that ozone depletion occurs over the QXP in summer， forming a bicentric structure known as the QXP Ozone Valley.The study also shows that typical El Ni?o events contribute to ozone depletion in the UTLS region over the QXP， while typical La Ni?a events have the opposite effect， weakening ozone depletion.Under the influence of El Ni?o， a negative sea surface temperature （SST） anomaly forms in the western Pacific Ocean， generating a Rossby wave at 200 hPa height that transports westward to the Indian Ocean.This strengthens the Bay of Bengal trough behind the QXP， causing lower airflow to converge and rise， shifting air from the troposphere to the lower stratosphere.At the same time， southward pressure and high pressure strengthen， resulting in a smaller Total Column Ozone （TCO*） zonal deviation than the multi-year anomaly and a decrease in ozone content.In contrast， under the influence of La Ni?a， anomalous warming of the sea surface in the western Pacific Ocean causes air flow over the QXP to sink and wind field to blow from the stratosphere to the troposphere.The weakening of southern pressure high pressure leads to a larger TCO* value than the multi-year anomaly and an increase in ozone content.Therefore， El Ni?o enhances ozone depletion over the QXP， while La Ni?a weakens it.