This study aims to address the issue that existing water surface evaporation models do not account for the unique characteristics of the narrow and long channel type of the Three Gorges Reservoir. By analyzing water surface evaporation data from the Badong station in the Three Gorges Reservoir, we develop a water surface evaporation model specifically tailored for the Three Gorges Reservoir by introducing functions for water vapor temperature difference under different wind speeds in consideration of the influences of four primary factors: saturated water vapor pressure difference, relative humidity, wind speed, and vapor temperature difference. Results demonstrate that the proposed model accurately simulates the reservoir’s water surface evaporation, particularly during the calibration period, achieving a Nash efficiency coefficient (NSE) of 0.75, a significant improvement from 0.31 obtained with other traditional empirical models. The model’s simulated evaporation values closely match measurements from five additional stations in the reservoir, validating its accuracy and reliability. This model provides valuable technical support for the rational utilization and scientific management of water resources in the Three Gorges Reservoir.