Through studying multiple cases on public opinion propagation under the background of emergency， the classifications of masses and the intervention effects of the government are first defined，and the state-tran-sition relationship between different types of the masses is also analyzed． Then，according to the practical characteristics of public opinion propagation，a control system of public opinion propagation with the considera-tion of the government’s intervention is constructed by applying the SEIＲ epidemic model． Further，the mean field method is used to present a differential equations model for the above system，and the government’s cop-ing strategies are obtained through studying the equilibrium points and the stability of this model． Finally，the public opinion propagation of the Great East Japan Earthquake in 2011 is taken as a case，in which the influ-ences of different focuses of government’s emergency decision on the behaviors of the masses are tested through designing multiple scenarios，and some related strategies are proposed for making emergency schemes．