Abstract: For reservoirs with water supply and irrigation tasks as the main tasks, scientific drought scheduling in dry years is particularly important for ensuring the ecology of downstream rivers and efficient utilization of water resources. The drought warning water level is an important reference indicator for issuing drought warnings and initiating drought response mechanisms.Taking a reservoir in the southeast coast in China as an example, the water supply, irrigation and ecological requirements of the reservoir are calculated. Through a long series of adjustment calculations, the guaranteed and restricted water supply lines of the reservoir are drawn. The two regulation lines divide the reservoir into three operating areas on an annual basis, and the drought warning water level of the reservoir is determined by stages and levels based on the operating areas. On this basis, the comprehensive scheduling methods for water supply, irrigation, and ecological discharge of reservoirs were explored, and the rationality of the scheduling methods was analyzed. Provide experience for drought scheduling in reservoirs with water supply and irrigation tasks as the main tasks during dry years.