Under global climate warming, the frequent occurrence of extreme weather events has caused great economic losses, thus, as a scientific issue, researching on regional extreme climate change has remarkable significance. In this study, based on the daily temperature data of 11 meteorological stations from 1971 to 2014 in Inner Mongolia Daxing'anling forest region, analyzed the spatio- temporal characteristics of extreme hot weather, extreme cold weather and the biological growth season in recent 50 years, using the methods of Linear trend, Morlet wavelet, Mann-Kendall and Kriging interpolation. The results are as follows: In the last 44 years, the extreme hot temperature days and biological growth season were on the rise significantly(P<0.001), the rates of change were 7.6 d/10a and 3.1 d/10a respectively, especially increased with larger scales after the middle of 1980s. However, the extreme cold temperature days showed a downward trend(-5.4 d/10a), and after the mid 1990s, the trend became weaker. From the perspective of spatial distribution, the extreme hot weather days and biological growth season showed an upward trend at all sites, while the extreme cold weather days showed a downward trend, but the spatial difference was obvious. The extreme minimum temperature has 27 a, 18 a,11 a, 7 a periodic changes, that played a major role in the extreme low temperature weather, of these, 27 a cycle time scale was considered the first main period. The extreme maximum temperature contained the cyclical in a number of different time scales, the 28 years periodic oscillation was most strongly, was considered the first main period, and played the most significant effect on the extreme maximum temperature, over the next 8 years (2019-2026) extreme hot weather may be more frequent. The growth season mainly was affected by 28 a cycle time scale, and in 2015-2022 with a higher growth period. This result will provide a powerful scientific basis for revealing extreme climatic changes in high latitudes in China, and provide reference for forestry production, agricultural production and disaster prevention and reduction in Inner Mongolia Daxing'anling forest region.