Abstract: The dynamic control of operating water levels at the Three Gorges Reservoir has established a preliminary basis, yet the specific control conditions for August require thorough investigation. Implementing dynamic water level control during August can reduce ecological and environmental impacts during reservoir impoundment while enhancing comprehensive reservoir benefits. This study develops a hydrodynamic simulation model for Lianhuatang water levels under varying hydrological conditions, and analyzes dynamic control range and conditions for August operations, considering flood control requirements and compound flood dynamics in the Chenglingji area. The results show that: ① The Chenglingji area remains below warning levels when the combined inflows from the Three Gorges Reservoir and the Dongting four-river system are less than 51 000 m³/s. ② After August 1, when the real-time Dongting four-river inflows are less than 15 000 m³/s with Lianhuatang station levels under 29.5 m, and no medium-intensity or heavier rainfall is forecasted in the Dongting Lake basin in the next week, the operating water levels of the Three Gorges Reservoir can be dynamically controlled between 145 m and 155 m. These findings provide technical support for comprehensive utilization of water resources in the Three Gorges Reservoir, particularly for storing drought-relief water resources during potential abrupt transitions from flood to drought after August, enabling integrated flood-drought mitigation.