Based on the data of Arctic sea ice concentration, sea ice extent, atmospheric circulation and sea surface temperature, the spatial and temporal changes of Arctic sea ice in autumn and their causes in 1982-2001 and 2002-2021 are studied. The results show that in recent 20 years (from 2002 to 2021), the falling center of Arctic sea ice aggregation degree has shifted from the Chukchi Sea and the Bering Strait in the past (1982-2001) to the Barents Sea close to the coast of Eurasian Continent (2002-2021), and the Arctic sea ice extent reduction has increased from 0.44×10⁶ km² in 1982-2001 to 0.72×10⁶ km² in 2002-2021 per decade, the reduction speed accelerated about 64%. The Arctic sea ice extent in autumn has a significant negative correlation with seawater surface temperature (SST), surface air temperature (SAT) and specific humidity (SH) and the correlation coefficients in the period of 2002-2021 are higher than those in 1982-2001, with the month when the correlation coefficient with temperature is the highest being advanced one month earlier. Through the analysis of SST, SAT, SH, sea level pressure (SLP) and wind field by using Empirical Orthogonal Function (EOF), it can be seen that the rising centers of temperature and SH in the Arctic Ocean are concentrated in the Chukchi Sea and the Bering Strait in the period of 1982-2001 and transferred to the Barents Sea during 2002-2021. The SLP and wind field also show the changes of center transfer in these two periods of time. It is the variations of the atmospheric and oceanic circulation factors that influence the melting of the Arctic sea ice.