Abstract: According to the observed data of starting works dredging river and strengthening dike in narrow reach of the lower Yellow River in 1997, the effect of dredging river on erosion-deposition variation in the channel and regulation of water surface profile is analyzed.The results show that the dredging river has a good effect on reducing channel's deposition and lowering flood stage in a certain period and a certain reach.The basic concept of effect on dredging sediment for deposition reduction is discussed also.