Using the daily meteorological data from 1961 to 2010 in the middle and lower Yangtze River reaches, this paper analyzed decadal variations of the spring waterlogging disaster and the risk of winter wheat loss suffered from spring waterlogging disaster by monitoring index model and assessment model. The results showed that winter wheat suffering from spring waterlogging disaster occurred frequently in the south regions of Yangtze River reaches, causing reduction in output for more than 30% years. And also, the decadal variations of risk of winter wheat loss due to spring waterlogging disaster are significant, with the features that highest risk ranges are maximal in the 1960s, which followed by the 1970s and 1990s, and the highrisk areas are the smallest in the 2000s, with scattering features in Jiangnan regions. At the 30 a scale, the regions of high risk area of spring waterlogging disaster are gradually decreasing, and the lower risk areas are increasing.
Key words：in middle and lower Yangtze River reaches; spring waterlogging disaster of wheat; the loss risk; decadal variation