Abstract: In order to predict the effect of the river improvement on the channel evolvement at the wandering-braided reach of the lower Yellow River,based on the theory of fluvial dynamics,the complex ersponse of the channel changes to the river improvement at the wandering-braided reach of the lower Yellow River is studied by the physical model experiment.The results show that the regulation of channel section is related to the restrainted degree of man-made boundary,flow variation and sediment concentration.When the plan layout of regulation project system is reasonable and the quantity is enough,the channel section will be developed to a narrow and deep channel by river improvement,which will make the wandering-braided reach into a restricted tortuous channel.Meanwhile,the flood carrying capacity and sediment transport competency are increased.The regulation of fall at different reach doedn't develop parallelly after the river improvement.