Abstract: The research on medical surge capacity and capability of medical institutions is a supplement to the research on the planning, mitigation, and response of the medical system in response to mass casualty incidents and of far - reaching policy significance. Based on the concept and key elements of medical institutions′ medical surge capacity and capability, this study divides the surge in demand for injuries caused by mass casualty incidents into two categories, the surge demand for intra - regional injuries and the surge demand for cross - regional injuries. The key issues and countermeasures that should be considered in the evaluation framework for different types of medical surge capacity and capability are pointed out to provide a theoretical basis for further construction of relevant index system.