Emergency management of unexpected accident can be viewed as a complex system, which is mixed with human thinking and based on social layers. It is featured with complexity, fluidity and uncertainty. Obviously, traditional management theory and methodology based on isolated thinking won't fit the studies on complicated issues. Based on practical studies on the current status of Wuhan's emergency management of unexpected accident, this article utilizes systematic thinking as well as the fundamental theories of complexity science management (CSM) - CSM integration theory, CSM overall theory, CSM new resource theory, CSM interaction theory, and CSM disorder-order theory. Under the guidance of these theories and the latest research findings from crisis management studies from home and abroad, this article proposes a plan to establish emergency management system to effectively handle unexpected accidents specific to the detailed situation of Wuhan. It will provide much-needed reference for the Wuhan city government to build an emergency management system.