Based on the daily temperature data from 46 meteorological stations in Inner Mongolia during the period from 1960 to 2014, the spatiotemporal variations of extreme temperature events in the study area were investigated. The RClimDex software was used to calculate and analyze the 12 kinds of extreme temperature indices released by WMO. The results revealed that,in recent 55 years,the extreme temperature indices in Inner Mongolia were in sync with global warming trend, the ID0 ,FD0 ,TN10 and TX10 were gradually decreased,whereas the SU25,TR20, TN90 and TX90 were significantly increased. TXx and TNn were in an increase trend,however DTR was tended to decrease. Spatially, the most obvious trend of extreme temperature occurred in west Inner Mongolia, and the bare underlying surface was highly sensitive to climate change. The temperature increase during the period of 1986 - 2014 was more significant than that during the period of 1960 - 1985. During this period, the cold indices (ID0, FD0, TN10 and TX10) were significantly decreased,but the heat indices (SU25 ,TR20,TN90 and TX90) were obviously increased. Moreover, the change trend of extreme temperature indices at the stations was complex before 1985, but the cold (heat) indices at almost all stations were decreased (increased) after 1986. The correlations between the extreme temperature indices and the latitude and elevation were weak, but it was strong with longitude. The Arctic Oscillation (AO) affected climate change in Inner Mongolia to a certain extent,and AO had the significant correlations with the extreme temperature indices, especially with the cold indices.