Abstract: Using data from Yichang and Wuhan hydrological stations of the Changjiang River Valley from May to September 1998 and soil moisture data before the floods occurred, causes for the disastrous floods are analyzed and a comparison is made with 1954. The results indicate that the summer flood mainly resulted from persistent heavy rain pattern. Other factors contributing to the flood include above-normal soil moisture levels and below-normal evaporation before the flood season. The large-scale atmospheric circulation patterns during the summer of 1998 were similar to the patterns associated with the historic heavy rain event.