Abstract: In order to study the spatial and temporal distribution of rainstorm days in Hunlun Buir and to guard against the impact on agriculture from flood disasters caused by rainstorm, the daily precipitation data from 16 meterological stations in Hunlun Buir Area during 1960-2010, through linear trend analysis and Mann-Kendall catastrophe test, composite analysis were analyzed in the spatial and temporal distribution characteristics and their variation of rainstorm days in Hunlun Buir Area. The results showed that: rainstorm days tendsed to be less in recent 51 years; heavy rain in this area was obviously distributed by seasons, the heavy rain started in May of spring and ended in September of fall, most of the heavy rain were in summer, especially concentrated in late July and early August. Rainstorm in this area was also obviously distributed by regions, and most of the heavy rain was on the hillside between the southeastern of Daxing’an Mountains and the Songnen Plain. The abrupt change of rainstorm happened in 1997, the rainstorm days had a trend of quickly reduced after abruption.