Abstract: Accurate and timely hydrometeorological forecast is the basis of reservoir optimal operation. After the completion of the Three Gorges Reservoir, the hydrological and hydraulic characteristics of the reservoir have changed greatly. On the basis of the original forecasting method, through continuous improvement and innovation, the Forecast Center of Hydrology Bureau of Changjiang Water Resources Commission developed a zoned medium-term areal rainfall forecast model based on a battery of numerical forecast models for the upstream Yangtze River and employed MIKE 11 hydraulics forecast model to forecast inflow entering the Three Gorges Reservoir.Based on the zoned area rainfall forecast and the medium-term inflow forecast entering the Three Gorges Reservoir issued by Hydrology Bureau during 2010 to 2017, this paper analyzes the forecast accuracy of the areal rainfall and the inflow entering the Three Gorges Reservoir and the possible causes of the forecast error, and prospects the development trend of the medium term hydrological and meteorological forecast in the future.