Aiming at the mismatch problem in the operation process existing in reservoir scheduling plan management, a reservoir optimal operation model based on scheduling plans was proposed. This model takes the objective functions of minimizing water shortage for water users and minimizing deviation from power generation plans. The particle swarm optimization algorithm was used to optimize the power generation plan. The model was used to analyze the matching degree between the water supply and power generation processes, the change of reservoir storage capacity, and the monthly benefit transfer relationship of power generation capacity of the Dalong Reservoir in Sanya City. On the premise of ensuring the water supply plan, the deviation of the optimized power generation plan at 50%, 75%, and 90% inflow frequencies decreased from 0.144, 1.961, and 3.033 to 0.131, 0.566, and 1.404, respectively. The power generation increased by 0.02 million, 5.6 million, and 4.7 million kWh, respectively. This indicates that adjusting the power generation and water supply processes can effectively improve the rationality of the scheduling plan.