This paper defines a group of seasonal and monthly mean new circulation indices of Aleutian low(AL) at 1 000 hPa in winter,including intensity(P),area(S) and central position(λ_c,φ_c).The circulation indices are calculated by using the NCEP/NCAR monthly mean height field at 1 000 hPa during 60 winters from 1948/1949 to 2007/2008.The climatological and anomalous characteristics of AL are analyzed by the circulation indices,focused on analyzing the correlation relationships between circulation indices(P and λ_c) with sea surface temperature(SST) in Pacific,temperatures and precipitation in the Northern Hemisphere during the corresponding period,respectively.Results show that:1)AL is the strongest with the center lying to the south and west of the normal position in January,the weakest with the center lying to the north and east in December,and the middle in February.2)There is a negative correlation between P and λ_c,with the center lying to the east of the normal(λ'>0) in the AL strong years(P'<0) and to the west in the weak years.On the interdecadal scale,AL has continued to be strong and eastward since 1970s,but there are reversing signs in recent years.3)AL is stronger and lies to the east of the normal in the strong El Niño years,and it is opposite in the strong La Niña years,which is particularly evident after 1975.There is a significant positive correlation between AL and SST in the mid-latitude Pacific,with AL strengthening and moving eastward in the SST negative anomaly years.4)The significant correlation zones distribute as the great circle wave train of "+-+" signs between AL index(P) and temperature,precipitation over the mid-and high-latitudes in the Northern Hemisphere during the same period,respectively.The correlation centers locate in the mid-latitude North Pacific,northwest and south of North America,close to the PNA(Pacific-North America) teleconnection pattern,whereas there are obvious differences between them in the tropical regions of the Northern Hemisphere.AL and Mongolian high are two adjacent atmosphere activity centers over the mid-and high-latitudes in the Northern Hemisphere in winter,but their correlation relationships with the El Niño/La Niña events,temperature and precipitation in the Northern Hemisphere during the same period are significantly different,which are questions worthy of further study.