Abstract: Using the daily mean,maximum,and minimum surface air temperatures (abbreviated as T_mean,T_max,and T_min) data from CN05.2 for the period from 1961 to 2012,the temperature decline events (TDEs) were determined in the present study.These TDEs were classified into three categories according to the range of temperature dropping,i.e.,the weak decrease in temperature (WDT),normal decrease in temperature (NDT),and a strong decrease in temperature (SDT).The temporal and spatial distribution characteristics of the occurrence frequency of TDEs were examined in this paper.Results show that,for T_mean and T_min,the highest frequency of the occurrence of WDT and NDT appears in the Daxing'anling Mountain,Xiaoxing'anling Mountain and Changbai Mountain,but the highest frequency of the occurrence of SDT appears only in Changbai Mountain.In addition,the three TDE category events happen frequently in 1960s and 1970s,but less in 2000s.For T_max,the highest frequency of occurrence of the WDT and NDT appears in a belt area among 42°-45°N,but less in north and south of this belt,showing a frequency distribution pattern of low-high-low.The highest frequency of the SDT events appears only in Changbai Mountain.The events of the WDT,NDT and SDT mostly happen in 1960s and 1970s,but very less in 2000s.