【Objective】This paper aims to analyze the change in occurrence of drought and flooding in Daxing anling forest in Inner Mongolia due to climate change and to provide baseline for studying the occurrence of drought and flooding, as well as ecological restoration and disaster prevention.【Method】Based on the measured average daily temperature and precipitation from 1971 to 2015 in this region, we analyzed their relationship using linear regression, the Mann-Kendall test (Mann-Kendall) method and the standardized precipitation index(SPI). 【Result】①The annual precipitation showed an rising trend over the past 45years, with an increasing rate of 8.9 mm per decade although the increase was insignificant (failed the significant test). The annual mean temperature also showed a rising trend at significant level (p<0.001) with a rising rate of 0.4 ℃ per decade. ②The annual mean temperature in the forest area endured an sudden change in 1988, followed by a decrease in annual precipitation. ③ In the past 45 years, forest drought occurred frequently and in the 1970s and early 2000s, the value of SPI12 was less than 0. In the 1980s and 1990s and 2010s, however, there was a rise in precipitation, reducing the drought frequency.【Conclusion】Following the abrupt change in temperature in 1987, the forest areas saw an increase in both drought and waterlogging, becoming either extremely dry or wet. The SPI at annual scale reflects the change in precipitation in the region.