台灣位於西北太平洋的亞熱帶地區，且颱風頻繁，加上地形坡陡、川短流急，對於颱洪期間如何有效操作水庫之效益，以達到水庫蓄水與防洪減災為重要課題。在多水庫同時進行水庫防洪操作時，需考慮洪水洩放歷程，以避免造成下游匯流口發生嚴重人為失當引發的洪災問題；因此，本研究在探討多水庫聯合防洪操作之規劃，除考慮各水庫的防洪與蓄水之功能外，並考慮下游匯流口之洪水歷程。 本研究以多水庫操作最佳化為目標，運用多水庫防洪操作運轉辦法及相關水庫硬體限制建立防洪運轉模式，以搜尋多水庫防洪最佳洩放歷程，利用非優勢排序遺傳演算法(Non-dominate Sorting Genetic Algorithm , NSGA-II)搜尋水庫最佳洩放歷程，探討水庫操作之合理性。本研究以石門與翡翠兩水庫系統以及該匯流處為研究對象，以非優勢排序遺傳演算法搜尋之結果顯示將有效達到洪峰消減並儲存洪水以滿足期末水位以利未來供水運用。 Taiwan is located in the Northwestern Pacific Ocean subtropical jet stream monsoon district and frequently hit by Typhoon. Because the steep mountainous landform makes most of the rainfall flow immediately into the ocean with a few hours, the river cannot keep enough water for future use. Reservoirs have become the most import and effective floodwater storage facilities. The huge flood often exceeds the capacity of the reservoirs; consequently, attention must focus on improving the operational effectiveness and efficiency of existing reservoirs for maximizing the beneficial use of water storage and decreasing the flood peak stage downstream. Especially, for the flood operation of the multi-reservoir system, it should prevent the downstream from a serious man-made flood. This study proposes a multi-reservoir flood operation optimization model with linguistic flood control requirement and existing operational regulations for providing the information of rational multi-reservoir flood operating decisions. The approach involves formulating multi-reservoir flood operation as an optimization problem and using the non-dominate sorting genetic algorithm (NSGA-II) as searching engines. The proposed approach was applied to the problem of finding the optimal release and desired storage, taking the multi-reservoir system of Shihmen and Feitsui reservoirs as a case study. The decrease rates of flood peak of two reservoirs and the junction are considered as the multi-objective functions. The results demonstrated that NSGA-II could effectively provide rational flood operating decisions of the multi-reservoir system to reduce flood damage during typhoon periods and to increase final storage for future usages.