With Arctic and Antarctic 1°×1°(longitude×latitude)sea ice area index data and SLP data,it is investigated,by statistical methods,that the variation of sea ice both in Arctic and Antarctic and its relation to atmospheric circulation.It is found that,in the past years,sea ice in Antarctic declines in winter,spring and autumn,while it increases in summer.Sea ice in Arctic decreases in a certain degree in spring,summer and autumn,but its linear trend is not obvious in winter.Sea ices in Arctic and Antarctic have some abrupt changes in spring,summer,autumn and winter.The atmospheric circulation has remarkable differences before and after the abrupt changes of sea ices.