Abstract: Water and sediment change of the Three Major Outlets River (Ouchi, Hudu, Songzi rivers) to the Dongting Lake from the Jingjiang River in the middle Yangtze River is an important part of the Jingjiang River-Dongting Lake relation which is adjusted by the water-sediment change. The Three Gorges Reservoir has resulted in the significant reduction of diversion discharge in the Three Major Outlets River. Hydrological data (water level and discharge) were collected in five stations (Xinjiangkou and Shadaoguan stations at the Songzi inlet, Mituosi station at the Taipingkou inlet, Guanjiapu and Kangjiagang stations at the Ouchikou inlet) in 2003-2018, to fit five groups of empirical formulae for the diversion discharge calculation incorporating the effect of water level reduction at the inlet. Result shows that the diversion discharge of the Three Major Outlets is mainly a function of the water level in the inlet area. The simplified formulae of diversion discharge obtained are further modified using the channel gradient and water level drop at the inlet area, and channel width. In 2017-2018, the measured data in Guanjiapu and Kangjiagang stations of Ouchi River were used to verify the predicted values, 4.5% and 13.7% of relative error, respectively, 11.5% in the Mituoshi station of Hudu River, and 4.5% and 7.3% in Xinjiangkou and Shadaoguan stations of Songzi River, respectively. In summary, five modified empirical formulae are in good agreement with the measured data, which can be used to estimate the change of diversion discharge of the Three Major Outlets River affected by future water level dropping of the Jingjiang River.