The severest flood ever since 1991 stuck Huaihe valley in the summer of 2003, causing severe damages. In order to provide a better description of Huaihe valley flood's historical scenario, analysis of Huaihe valley flood's variation from 1470 to 2002 is made using precipitation data reconstructed from historical data during the pre-observational period together with the observational precipitation data. According to Huaihe valley flood's pattern compared with the allover precipitation distribution of China, especially its relationship with precipitation in Yangtze River valley and Yellow River valley, the floods of Huaihe valley can be classified to 2 main types. The first type is heavy precipitation in Yangtze River valley and Huaihe valley, rain belt mainly covers Yangtze River valley and extends to Huaihe valley. The second type is heavy precipitation in Yellow River valley and HuaiHe valley. At last the analysis of the 500hPa height fields of the 2 precipitation types is made.