Abstract: To address the issues of delays and economic barriers inherent in traditional mountain flood forecasting and early warning systems based on the rainfall–runoff response relationship, we have proposed a novel approach for the early identification of mountain flood hazards from an energy evolution perspective. By shifting the research focus from the apparent manifestations of disasters to their energy core, we systematically analyze the entire evolutionary mechanism of mountain flood hazards: “initial potential energy accumulation — initial conversion of potential energy at high positions to kinetic energy — accumulation of surface potential energy and convergence of kinetic energy”. To overcome the limitations of the traditional approach, namely, “sending alerts until rain comes, generating varied floods despite similar rainfall”, we have identified two key scientific issues (defining the conceptual framework for energy characterization indicators during mountain flood disasters and quantitatively mapping energy states) and two major technical bottlenecks (establishing an observation system for mountain flood energy evolution processes and constructing regional high-resolution continuous energy fields). The findings provide a theoretical foundation and technical pathway for shifting mountain flood disaster prevention from “passive response” to “proactive defense”.