Through the analysis for the autumn rain and flood process in September 2011in the middle and down stream of Weihe River, the results showed that the “11.9”flood in the down stream of Weihe River appeared some characteristics as high flood level, longer duration, peak flood reducing along the river and slow evolution between Lintong and Huaxian. From the aspects of sediment scouring and silting in the river channel, the changes of river regime and flood disasters, the paper discussed the impacts of flood on river channel in the down stream of Weihe River and put forward the flood control and disaster alleviation suggestions as reviewing the guarantee discharge and improving the standard for the flood control.