The emergency power used by the colleges is actually an expansion of administrative power and is inevitably related to legality, legitimacy, and effectiveness, which are interrelated and interinfluenced. Legitimacy is the basis for the use of emergency power and the most powerful guarantee for the use of emergency power, mainly composed of legal legitimacy and political legitimacy; rationality, a necessary complement to legitimacy, can provide a solid basis for the use of real emergency power; effectiveness, an important supportive condition, determines the legitimacy of the use of emergency powers.