Abstract: The Evolution of flood losses of the United States in the 20th century,the flood impact on national economy,and the responses after the great floods are explored in the paper. The comparative analysis of flood losses between the US and China in the 1990s is discussed. Some conclusions are obtained to provide the referees for the policy on flood control and disaster reduction in China as follows. Flood losses in the United States continued to rise slowly to US 5.56 billion of average annual damages in the 1990s at a ratio of 1.58 percent and the ratio of flood losses to GDP continued to drop gradually from 0.334 percent in the 1930s to 0.068 percent in the 1990s;many key policies involving flood were triggered by destructive floods to head the way from flood contain and control to flood management;with the comparative analysis of flood losses between the United States and China in the 1990s,average annual damage in China in the 1990s is estimated about RMB 134.34 billion accounting for a proportion of flood losses to GDP of 2.386 percent in contrast,average annual damage US 5.56 billion in the United States accounting for the ratio of 0.068 percent.