Abstract: Xinshu River is an important part of the“East Diversion”project in the south-east diversion project of Yishusi in Huaihe River Basin. The flood process is greatly influenced by human control and operation. In order to analyze the current flood discharge capacity of the lower reaches of Xinshu River,this paper uses the calculation formula of constant non-uniform flow of natural river to calculate the current flood discharge capacity of the river, according to the section and flow design data of the lower reaches of Xinshu River,the equivalent design section is calculated by the surface curve method through modifying the section parameters,and then the current design flow of Xinshu River regulation project is obtained by checking with the highest water level of typical flood,modifying the flow and calculating the water level to the design water level. The results show that:(1)The flood discharge capacity of the lower reaches of Xinshu River has basically stabilized after comprehensive treatment;(2)The current flood discharge capacity of the lower reaches of Xinshu River is only about 80% of the original design capacity; (3)The current flood discharge capacity of the lower reaches of Xinshu River is mainly affected by river siltation and human activities.