In recent years，multiple large-scale sand mining projects have often been carried out simultaneously in the same river reach of the lower Yangtze River. Compared with a single sand mining project，its impact on river flow conditions is more complicated. In this paper，a two-dimensional mathematical model is used to study the changes in water level，velocity，and diversion ratio of the channel under different sand mining schemes，and the superimposed effects of multiple sand mining projects implemented simultaneously are discussed. The results show that：1）The effect of a single sand mining project on the water level and velocity is mainly limited to the vicinity of the mining area，and the simultaneous implementation of multiple sand mining projects has reduced the water level and velocity variation caused by a single project. 2）After the implementation of a single project，the change of ebb tide diversion ratio is greater than that of flood tide diversion ratio，and the implementation of multiple projects has a small overlapping effect on the diversion pattern of the river section. 3）In addition，Tongzhousha west waterway mining project which located at the branch entrance section has the most significant impact on water flow conditions.