Abstract: In large-scale inter-basin open channel water transfer projects, all kinds of water conveyance elements are connected with each other, and their flow characteristics are different, an analysis of the hydraulic response characteristics of the ditch basin is of great significance for the safe and stable operation of the project. By constructing one-dimensional hydrodynamic model and taking safety regulation as guidance, the feasible time domain of safety regulation is analyzed. In order to avoid the occurrence of water level exceeding the limit, the earliest and the latest regulating time of the buildings that do not exceed the upper and lower limits of the water level of the canal pool are calculated, taking the upper and lower reaches of the pumping station in the river mouth of the Yangtze-Huaihe River Diversion Project as an example, the study is carried out. During the study, due to the selection of channel segment, the earliest regulation time was 0 h, so the latest regulation time is analyzed. The results show that:（1） when the initial upstream flow and downstream water level remain unchanged, the latest regulation time decreases with the increase in the target flow and flow variation in a power function relationship（2） When the initial upstream flow is the same and the flow variation is different, the latest regulation time gradually decreases with the increase in the downstream water level, and the decrease trend of the latest regulation time becomes gentler with the increase in flow variation；（3） The latest regulation time has the strongest correlation with the flow variation, but has a poor correlation with the upstream initial flow. Finally, based on the calculation results of feasible region of safety regulation time, a fast generation formula of the latest regulation time is constructed.