Abstract: Changes in heavy rain in Dandong were analyzed by using the daily precipitation data from the 4 meteorological stations of Dandong. The results indicate that both the annual heavy rain days and heavy rain amount in Dandong exhibited decreasing trends. However, the percentage of heavy rain amount to the total precipitation during the flood season from 1951 to 2009 showed no obvious trend. The heavy rain days increased obviously in June while decreased in July, and both the starting date and ending date came earlier in 2001-2009 than in the proceeding decades.