Abstract: Based on the flood data of China and annual precipitation data of eastern China since 1880, the paper discusses the change characteristics of flood disasters in China, and its relationship with precipitation change and human activities. The adopted methods include Mann-Kendall (MK) test, empirical mode decomposition (EMD) and correlation analysis. The results are as follows: 1) the magnification of flood disaster occurred in the late 19th century, the period during 1950s and 1960s, and the late 20th century. The magnification periods of flood disasters in the late 19th century and during 1950s and 1960s corresponded well with the wet periods, while the flood magnification period occurring in the late 20th century did not result from the increase in precipitation amount. 2) Moreover, multi-scale characteristics of flood disaster and precipitation have been detected. The main periods of flood disaster are 2.7-year, 5.2-year, 9.9-year, 20.5-year and 51.6-year, and the periods of precipitation series corresponds well with those of the flood disaster series. 3) The magnification of flood disasters in the 1980s and 1990s did not result from the increase in precipitation amount, while the increment of rainfall intensity and extreme rainfall events play an important role in the process. And the human factors such as aggravation of soil and water loss and lake reclamation are also the driving forces contributing to the increment of flood disaster. Additionally, there is significant negative relationship between flood change and strength of investment in water resources.

Key words: flood disaster, precipitation change, human activities, MK test, empirical mode decomposition