In recent years，there are a variety of emergencies have occurred all over the world because of the impact of global warming，economic globalization and changeable international political situation. As a result，the social stability has been harmed greatly. National and local governments have taken emergency management seriously，while academia and industry also have paid sufficient attention on the field. As an indispensable part of emergency management system，emergency case base helps the decision makers to index the useful advices quickly from historical data when a new emergency occurs. The report aims to solve the heterogeneity and fragment of the existing case bases in the view of knowledge engineering. As a starting point，the extensible metadata structure is developed to figure out the problem which is called as Information Island. On the other hand，different knowledge representation methods are analyzed and Framework notation is selected as the main method to represent the emergency case. Emergency Frame describes the static characteristics of emergency case while the flow of events is for the dynamic characteristics. Based on this idea，a Framework Network is built to represent the emergency case，where aggregation and dependency are used to note the concepts and their relationships with the guidance of the emergency management discipline. The research of the report has laid a semantic foundation for the following construction of emergency case base.