The Lower Jingjiang Reach exhibits inherent meandering tendency and natural cutoff characteristics. As a key node for river regime control in the middle Yangtze River, the Qigongling Bend, if subjected to natural cutoff, would impose significant adverse impacts on river channel stability, river-lake relations, and port and waterway safety. To clarify the natural cutoff process of this bend, this study conducted in-depth investigation on its dominant cutoff modes, defined the extreme hydrological conditions triggering natural cutoff, and quantitatively revealed the dynamic evolution process of natural cutoff, through analysis of measured hydrological data and theoretical formula calculations.The results show that cut-through cutoff and composite cutoff induced by extreme floods are the possible cutoff modes of the Qigongling Bend. The corresponding extreme hydrological combination is a discharge of 40,512 m3/s at Jianli Station, 23,688 m3/s at Chenglingji Station, and a water level of 31.12 m at Luoshan Station. There is a significant positive correlation between cutoff duration and channel roughness coefficient: within the roughness range of 0.025 to 0.037, the cutoff duration ranges from 65 h to 113 h. A scenario simulation with daily decreasing discharge after the extreme hydrological event was performed, which showed that the maximum erosion at the narrow neck exceeded the critical threshold for cutoff at the end of the 4th day, verifying the possibility of natural cutoff.This extreme hydrological combination corresponds to a discharge of approximately 54,000 m3/s at Zhicheng Station. The unfavorable combination of upstream large floods and low inflow in the middle reach is prone to inducing cutoff risk. This study presents preliminary findings, and further research is required to deepen hydrological frequency analysis and refined numerical simulations. Such hydrological combinations can serve as key concern scenarios for Three Gorges Reservoir operation and river channel inspections.