This paper analyses the policies of Qing water management,official administration, the techonology of water projects and their effects on the yellow River flooding after it changed its course at Tongwaxiang. In the late Qing Dynasty, because grain transpota - tion by the Great Canal, which was linked with closely with the control of the Yellow River. became less important, and also because of increasing political crisis which threatened Qing,rule, directly, the Qing government took water management as a kind of secondary problem. So the funds were greatly reduced and the water conservancy organization was was back. For these rensons. in addition to officials'corruption and backward technology, Yellow River flooding became an "incurable desease".