Abstract: Making mathematical description and analysis to the decision tree of urban emergency command organization on the basis of the design of collaboration net of emergency command organization of urban agglomeration,and making optimized design to the relationship of emergency command of major public security events of the corresponding urban agglomerations,using Yangtze River Delta Urban Agglomerations as the object of case analysis,so as to realize the effective collaboration of each city emergency command center among the urban agglomerations. As the result shows,if it is clear that the weights of the collaboration of each city among the urban agglomeration between the emergency command decision-making entities of urban agglomeration and the allocation plan of emergency command platform,it is able to analyze the optimized design scheme of major public security events emergency command relationship of the corresponding urban agglomeration,and we can establish an effective emergency command system in this way.