The invention discloses a water supply type reservoir operation chart dynamic control method based on runoff forecasting, and relates to the field of water resource management and water project management. The method comprises following steps: firstly, water supply dispatching calculation is carried out on all years time by time, and the problem of differences of typical year selection and the low assurance rate caused by few samples is solved; on the basis of a conventional water supply dispatching line calculation method, a control factor of a water coming situation is introduced, the opposite position of an operation line in an operation chart is selected as long-term, medium-term and short-term hydrological runoff forecasting, and dynamic control over the operation line under the different rich and low coming water situation; and the problem that according to an existing method, the typical year representativeness is insufficient, and forecasting incoming water is not considered is solved. The water coming and needing situation possibly appearing in reservoir water supply operation can be comprehensively covered, the water supply manner is dynamically controlled according to the rich and low condition of forecasting incoming water, and the aim of optimal utilization of water resources is achieved.