The Arctic Oscillation (AO) is spatially varies, but a long-term EOF will ignore this change in AO pattern. The 25-year running EOF shows that the spatial variation of the AO has its decadal variability, both the North Pacific Center and the Arctic Center shift eastward and its North Atlantic Center has an east-west shift. Furthmore, it corresponds with the change in Aleutian Low, Island Low and Azores High, which implies the AO has physical significance. With a detailed distinguish between early winter and late winter, the peak time for AO advances from late winter to early winter. This variation will change some phenomena which correlate with AO, such as extreme weather.