[Purpose/significance]The public opinion of serious natural disasters is a hot topic in the field of emergency management in China. To clarify the evolution law of the public opinion of serious natural disasters is an inevitable choice to improve the ability of disaster public opinion management and build an emergency management system with Chinese characteristics. [Method/process]Based on Laswell's "5W" communication model, according to the logical relationship of "the environment where evolution is located - who causes evolution- to whom evolution - what is the content of evolution - through what channels - how evolution effect", an element framework of public opinion evolution of serious natural disasters is built. Based on the life cycle of public opinion evolution, the complex interaction between various elements is explored, and the operation track of public opinion evolution of serious natural disasters is depicted. [Result/conclusion]By analyzing the coupling relationship of various elements in the dynamic process of public opinion evolution of serious natural disasters, the dynamic factors influencing the interaction of constituent elements are revealed, so as to fully grasp the evolution mechanism of public opinion of serious natural disasters.