Abstract: In order to explore the theoretical technology and method system for the formulation of ecological water replenishment schemes for seasonal rivers, this paper proposes an ecological water replenishment mutual feedback method combining ecological flow calculation and hydrodynamic model.Based on the diagnosis of hydrological sequence variation, this method lays a foundation for the formulation of ecological water replenishment scheme by calculating the ecological flow process in the river channel.Then, according to the actual process of ecological water replenishment, a hydrodynamic model of river ecological water replenishment is established and solved, which provides a model support for the study of ecological water replenishment evolution. Finally, the hydrodynamic model is used to analyze the water replenishment evolution of different water replenishment schemes, so as to obtain the best water replenishment scheme under the given target. By taking a seasonal river DY River in the north as an example, this paper carries out an application analysis. The results show that:（1） The variation point of TG reservoir inflow runoff sequence is 1980. On this basis, the runoff sequence can be divided into two parts: natural stage and human disturbance stage.（2） The ecological water replenishment scheme obtained by the ecological water replenishment mutual feedback method can not only meet the ecological flow demand in the river channel, but also fully consider the characteristics of the annual variation of the river runoff process, which is of important scientific significance for understanding the ecological flow restoration process of seasonal rivers in China；（3） The ecological water replenishment mutual feedback method is applied to the ecological water replenishment project of DY River, and the effect is good. According to the requirements of the ecological water replenishment target, the ecological water replenishment scheme that meets the water supply of the whole line in DY River is obtained, that is, when the ecological water replenishment of DY River is in spring, the optimal ecological water replenishment flow from March to May is 49.82, 27.17 and 8.67 m3/s. This method can be used for the subsequent DY River to formulate corresponding ecological water replenishment schemes for other water replenishment targets, and can also provide new methods and new ideas for the formulation of ecological water replenishment schemes for seasonal rivers in other basins.