Frequently occurrences of extreme climatic events in recent years have become a focus of sustainability research, because they threaten the ecosystem balance and even the sustainable development of social-ecological system. In this study, by the daily record data of 46 national meteorological stations in Inner Mongolia during the past 50 years, 15 indexes that characterize the frequency and probability of extreme climatic events are calculated with RclimDex (1.0). The trends and spatial pattern of extreme climatic events across this region were obtained. The results indicate that frost day (FD0), the percentile value of cold night (TN10p), the percentile value of cold day (TX10p) and the duration of coldness (CSDI) that characterize the extremely low temperature presented downward trends; meanwhile, summer day (SU25), crop growth period (GSL), the percentile value of warm night, the percentile value of warm day (TX90p) and the duration of warmness (WSDI) that characterize the extremely high temperature showed upward trends. Since the 1990s, the frequency and duration of extreme temperature events increased fast in comparison with the smooth trends from the 1960s to the late 1980s. Different from extreme temperature events, obvious extreme precipitation events variation started since the latest 10 years, heavy precipitation and 5-daily maximum precipitation were both much lower than those in the preceding 40 years. Extreme temperature indexes in 46 sites in the study area almost had the same variation process and there was no clear spatial differentiation. However, at some sites located in the farming-pastoral ecozone, heavy precipitation events occurred more frequently in recent 10 years than in the preceding 40 years, while the heavy precipitation events in recent 10 years occured less frequently than in the preceding periods at the other sites.