Abstract: Few of existed studies pay attention to the public opinion in emergency from the perspective of emergency attributes. The dynamic mechanism of public opinion's generation and propagation is firstly analyzed in the view of attributes by applying structural description of emergency. And structural description frameworks are constructed respectively for decision behavior and game relationship among propagation bodies. Then, cognitive differences are considered in different propagation bodies, and its utility function is introduced. Next, the game relationship is studied among the public, and the game relationship between the public and government departments through the approach of evolutionary game theory. Results show that the evolutionary equilibrium of the two kinds of game systems are respectively affected by the return functions of two game parties under different strategies combinations; both the systems have different evolutionary equilibrium under different constraints, and the government departments should choose the right moment when implementing their intervention strategies; the central government can conduct the related government departments to perform their duties better by taking appropriate rewards and punishments to them. Furthermore, numerical examples are taken to verify that cognitive differences have great influence on the game equilibrium. Finally, a case study of public opinion propagation is investigated to verify the validity of the conclusion. The results of this study can not only provide theoretical support for revealing the public opinion's generation mechanism and propagation law, but also provide reference for the government to guide or control the evolution direction of public opinion.

Key words: emergency, evolutionary game, evolutionary stable strategy, public opinion propagation