Abstract: Correctly describing the flow process near the breach site and the variation of breach discharge is essential to the prediction of overtopping flow and flood propagation,which provide valuable information for breach blocking and disaster preparation,as well as flood damage assessment.Based on the observational result from a series of bend flume experiments,the erosion process during overtopping breaching of non-cohesive embankments can be divided into four stages,overtopping,groove formation,breach stretching and stability.The analysis involves the variation in water levels and flood discharge in the river after overtopping breaching,the water-level difference between the inner and cuter river,and the influence of embankment materials on water-level changer near the breach site.Finally,the study snmmarizes the relationship among the breaching discharge,the breach width and the water head near the site.