Abstract: With high temperature days data from 16 stations in Hulun Buir during 1960—2012,the results showed that the geographical distribution of high temperature days were unevenness. The days of southwestern area were the most, followed by central and southeastern area, the northern area were the least. Hot weather occured in May to September, most appeared in June to August, up to June, September least. The maximum Interdecadal change of high temperature was the end of the1990 s to the first decade of this century, then the early 1980 s, followed by the late 1960 s, particularly small number of high temperature days was the late 1980 s. In the recent 53 years, the extreme maximum temperature was 42.5 ℃,which appeared on the July 21 th in 2004 at Xinbaerhuyouqi.