The second mode of 200 hPa meridional wind over the Eurasian continent, known as the North Atlantic-East and North Asia (NAENA) pattern, has a significant impact on the multi-scale climatic variability in Eurasia.This paper examined the NAENA pattern's influence on summer drought and flood anomalies in Xinjiang, China, as well as its possible mechanism, based on an analysis of the NAENA pattern's maintenance mechanism.The vorticity budget analysis of atmospheric wave train shows that the advection of perturbed vorticity by the climatological rotational zonal wind can be compensated by the advection of mean vorticity caused by the anomalous rotational meridional wind.The energy conversion analysis indicates that the NAENA pattern is maintained mainly through the baroclinic energy conversion from the basic flow with the North Atlantic SST tripolar pattern being the important external driving factor for maintaining the NAENA pattern.Moreover, regression analysis shows that the NAENA pattern can significantly affect drought and flood anomalies in Xinjiang by promoting Southern Xinjiang summer precipitation.When the NAENA pattern is in phase with a cyclone over Central Asia, the vertical ascending motion in Southern Xinjiang tends to be above normal;however, more water vapor is transported into Southern Xinjiang, leading to an anomalous increase in precipitation over Xinjiang.This study is of great significance because it reveals the mechanisms of summer drought and flood in arid areas of northwest China, which is conducive to climate prediction and disaster prevention and mitigation.