Based on flow and water level sequence data from six stations, we analyzed the changes in water level of floods of different frequencies, thereby obtaining the flood regime variation in the tail channel of Ganjiang River. Results revealed a general decrease in flood levels in the tail channel of Ganjiang River, with the average highest flood level in 2003-2022 dropping by 0.24 to 1.65 meters compared to 1956-2002. Flood levels at various frequencies have reduced to varying extents, with control sections for lake flood remaining stable, while control sections for river flood significantly decreasing, declining by 1.62-1.77 meters to the maximum. Such declines indicate an enhanced flood carrying capacity of the corresponding river section, which means alleviated flood control pressure and improved flood control safety. Future flood control and engineering designs should consider scenarios of encountering both river flood and lake flood at the Ganjiang River tail channel, and the impact of such extreme situations should be thoroughly examined.