Yokohama, a city in Japan, has achieved great success with building up a comprehensively planned and efficient urban emergency management system under the strategy and policy guidance of "concentrating on prevention and substantial results". The strategy and policy has categorized and considered all possible and potential crises as objects in crisis management, according to their different sources. The paper targeted the crisis management mechanism in Yokohama as the research object, focused on the case of new influenza crisis management mechanism and launched a comprehensive investigation on emergency response mechanism in Yokohama city. <<