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By using ERA-I reanalysis data and the reforecast and forecast data of NCEP CFSv2, the inter-decadal shift in the stratospheric polar vortex boundary in winter and autumn in the Northern Hemisphere since the 1980s is analyzed, and the ability of CFSv2 to simulate the polar vortex boundary is evaluated. The results show that from 1980 to 2017, the Arctic polar vortex retreated northward in North America and expanded southward in Eurasia in winter, but the polar vortex expanded in North America and retreated in Europe in autumn. The polar vortex expanded significantly from the 1980s to the 2000s and retreated in the 2010s in Asia. In winter, the retraction of the polar vortex occurred mainly in the 1990s in North America, and the expansion of the polar vortex occurred mainly in the 2000s in Europe and in the 1990s in Asia. In autumn, the southern expansion of the polar vortex boundary in North America mainly occurred in the 1990s, the retraction of the polar vortex in Eurasia occurred in the 2010s. The overall trend of the winter polar vortex boundary and area simulated by CFSv2 is consistent with that simulated by the ERA-I data in the 1980–2010s, especially for the expansion trend in North America and Asia in the 2010s. The simulation of the boundary and area of the polar vortex by the CFSv2 in autumn is poorer than that in winter; the simulation of the overall trends in the polar vortex boundary and area change is poor. • At present, there are few studies on changes of the polar vortex boundary in autumn. • In winter, the Arctic polar vortex retreated northward in North America and expanded southward in Eurasia. • In this paper we analyzed and evaluated the simulation level of the stratospheric polar vortex shift events. • The simulation of the boundary and area of the polar vortex by the CFSv2 in autumn is poorer than that in winter. [ABSTRACT FROM AUTHOR]