Abstract: Global warming has led to significant warming in the Arctic region, resulting in a drastic retreat of sea ice. Previous studies have revealed that the sea ice condition in the Barents Sea region in autumn is a crucial precursor factor for temperature anomalies in Eurasia in late winter. Although the activity of the low-level anticyclone in Siberia during winter is closely related to changes in cold air, whether and how Arctic sea ice affects the activity of the low-level anticyclone or cold high-pressure systems in winter in Siberia remains unclear. In this study, the effects and pathways of low sea ice in autumn in the Barents Sea region on anticyclone activities in Siberia were investigated using ERA5 reanalysis data and sea ice data. The results revealed the following: (1) Interannual variations in autumn sea ice density in the Barents Sea region affect the winter anticyclones and the quality of the cold air they carry in the Siberian region. The anticyclone activity is enhanced, and the cold air it carries increases when there is a reduction in sea ice in the autumn. (2) An exponential reduction in sea ice area in autumn leads to enhanced ocean heat transfer to the atmosphere later in the season, thus reducing the meridional temperature gradient between the polar regions and mid-latitudes in winter. This, in turn, weakens the mid-latitude westerly winds, resulting in increased anticyclonic activity in Eurasia. (3) The authors designed a sensitivity test for sea ice changes in the Barents Sea region using the atmospheric circulation model CAM6. The test results reproduced that under conditions of low sea ice, most of the Eurasian continent, except for the area to the east of Lake Baikal and northeastern China, experienced an increase in anticyclone frequency and enhancement of the central pressure of the anticyclone. In particular, the reduction in sea ice caused a significant decrease in the meridional gradient of the vortex, leading to an increase in the frequency of blockages in the East European Plain, the Ural Mountains, and East Asia, resulting in enhanced anticyclone activity and reduced temperature in most of the mid-latitude regions of the Eurasian continent.