Abstract: Extreme precipitation, severe flooding, widespread droughts, and compound disasters occur more frequently as the "non-stationary" features of the global water cycle become more obvious. When confronted with "low-probability, high-impact" natural disasters, the traditional approach of "defense based on historical patterns," which assumes climate stationarity, suffers from a lack of adaptation. By investigating the conceptual chain of "flood-drought-disaster-impact-prevention-resilience," this study points out a systemic bias in the present approach. This bias emphasizes structural prevention over adaptive resilience and disaster control over damage mitigation. We establish a new paradigm of "intelligent adaptation to uncertain extreme" in response, along with its practical applications. According to the study, a modernized flood and drought defense system should: apply the National Water Network as a strategic carrier to improve spatiotemporal water reallocation capacity; use smart water management as the main driver for establishing a closed-loop system that combines "monitoring-forecasting-simulation-decision making"; with ecological measures as a resilience foundation to promote "grey-green synergy" in systemic governance. Additionally, the perspectives of energy dynamics and social psychology expand the theoretical bounds of disaster comprehension and defense evaluation. The aim of this study is to offer a theoretical foundation and workable solutions to establish a new-generation flood and drought mitigation system that will withstand unpredictable conditions in the future.