Abstract: Urban governance is a real problem faced by all kinds of cities in the world today, and also a theoretical problem faced by scholars of urban studies. How urban governance can quickly shift from the state of conventional governance to the state of emergency governance in order to effectively respond to unexpected disasters, and then smoothly shift from the state of emergency governance to the state of conventional governance, thus forming a dynamic evolutionary process of urban governance, is an important challenge for urban governance and an urgent global issue that needs to be solved. The fundamental solution is to build and improve a scientific, systematic and complete dynamic evolutionary mechanism of urban governance. The research on the dynamic evolution mechanism of urban governance should pay great attention to both the conventional urban governance mechanism and the interactive transformation of the conventional urban governance mechanism and the emergency governance mechanism, and the construction and improvement of the emergency governance mechanism in case of unexpected disasters, to achieve the coordination and unity of the whole situation and the focus, and the orderly transformation of the static and dynamic in the whole process of the dynamic evolution of urban governance mechanism. In view of the above issues, this paper argues that the connotation of urban governance and its mechanism must emphasize both static and dynamic governance, conventional and emergency governance; the soundness of urban emergency governance mechanism is an important institutional foundation in the whole process of dynamic evolution of urban governance mechanism.