In order to improve the effectiveness of reservoir water diversion in intake area of inter-basin water transfer project, reservoir operation charts of inter-basin water transfer in intake area by coupling mid-and long-term runoff forecast were studied based on the parameter-simulation-optimization (PSO) model. Through the case study in the Biliuhe reservoir, the methods of employing long-term forecast to modify the upper and lower limitations of the water division rules, and “storage plus mid-term runoff forecast” were proposed. The different forecast operation methods were compared for the simulated results and operation risk analysis. The rationality of coupling the mid-term and long-term runoff forecast operation charts was analyzed. The results showed that the coupling mid-and long-term runoff forecast operation charts could reduce the inter-basin diverted water effectively, improve the utilization efficiency of water resources, and reduce the water shortage risks compared with the operation charts by only using long-term runoff forecast.