中文摘要：

采用1644—1839年、1840—1949年中国洪涝受灾县数和1950—2004年中国洪涝受灾面积资料，经过去趋势标准化处理后，采用滑动功率谱和Bunerworth滤波器进行了分析，得出：1644—2004年间中国洪涝受灾范围变化是不同时间尺度周期振荡的综合结果，主要包含80年的世纪周期和50年、30年、20年尺度的年代际周期。中国洪涝受灾范围变化的主周期在不同时段内存在明显的变化，1833年以前世纪周期变化显著；1834—1920年在世纪周期变化的背景下叠加了显著的20年尺度波动；1921年以后年代际尺度周期变化显著，其中1947年前后发生了主周期从20年尺度到30年尺度的变化。

英文摘要：

Based on the data of the number of flood hazard counties during 1644 - 1839 and 1840 - 1949 and the area of flooded cropland during 1950 - 2004, the periodic features of flood disaster over China since 1644 are analyzed in this paper. A uniform flood disaster series is established by the removing trend from the original data and standardizing the data then in each interval in order to make the data from different sources comparable and remove the effect of human factors. The methods of the classical spectrum analysis and Butterworth filter are used to analyze the standard series. It is found that （1） changes of flood disaster over China during 1644 - 2004 is an integration of the different time-scale periodic oscillations dominated by the scales of 80 year, 50-year, 30-year and 20-year, and （2） the dominant periods are different in different times, which are the centennial scale oscillation during 1644 - 1833, and the 20-year scale periodic oscillation is sensitive in addition to the centen- nial scale oscillation during 1833 - 1920, while the inter-decadal periodic oscillation is dominant after 1921 within which a change from 20-year to 30-year scale occurred in 1947.