Abstract:At present, China is not only in a crucial period for social transition and further reform, but also in a special stage of predominantly the social problems and social contradictions. In essence, the rumor as a specific social phenomenon to spread has great destructive power. The spread and diffusion of the rumor can easily lead to social panic, increase the cost of social governance, disturb the public order, and threaten the social stability operation. Therefore, how to management social rumors effectively, reduce the harmfulness of social rumors, avoid the panic which caused by falsity information, and maintain the public order and morals of society, the research on the social rumor and its transmission dynamics has become the top priority to China’ s social governance. This article chooses the social rumor and its transmission dynamics as the fundamental point, gives a clear concept of social rumors, and proposes three basic properties inherent in the meaning of social rumors, they are time attributes, spatial attributes, and social harmfulness. Above these, from the theoretical and practical aspects, this paper reviews the spread and diffusion of social rumors in the developed countries like United States, Great Britain, Germany, Japan, and some emerging market countries like China, India. In order to govern social rumors effectively, governments of the world either promulgate relevant laws, or take multiple measures to jointly combat this global“public enemy.” At the same time, many cities in the world have set up“the Center for Rumor Control”. The officials are called upon to resolve social rumors in the nick of time. The Social Stability Early-warning research group in the CAS began to study the issues of rumor from 2004, and has been discussing related issues from the perspective of social physics. Currently, it has achieved preliminary research results on the generation, development, evolution of social rumors and how to identify them effectively. The classical model of forest fires, as an important ideological source of social physics, is typicality and necessity to the introduction of social rumors’ spread and diffusion analysis. According to guidance of Social Combustion Theory in social physics, and combined with the classical model of forest fires, this article makes a deep analysis in the spread and diffusion mechanism of social rumors. The spread of social rumors is also a complex phenomenon of Social Combustion Theory. The unbalanced social environment is the soil for social rumors’ breeding. The social fundamental contradiction, extreme expression of social emotions can be seen as the basic motivation of social rumors’ birth, which is the“burning material”. The public as rumor receptors can be regarded as combustible materials. The different moisture content in combustible materials will determine the extent of its spread. Likewise, the extent of the public’ s susceptibility will affect the propagation velocity of social rumors. Similar to the wind in the nature（like wind direction, wind speed）, the one-sided report of the alternative media, add fuel to the fire by the opinion leaders, the news which is announced by official media, the positive propaganda, etc. will aggravate or decelerate the spread of social rumors to some extent. At the same time, there exist the factors of gradient in social rumors spread. If social rumors keep the same way with mainstream public opinion environment and social prejudice, it will contribute to the diffusion of rumors, which is equivalent to the spread of forest fires on the uphill. If we process and disposal some sensitive information in time, which is equivalent to the establishment of the buffer zone, the diffusion of social rumors can slow down to some extent. Combined with time-space feature of forest fires, like ignition temperature, rate of spread and burn material, etc. the diffusion equation of social rumors is established. Based on the above analysis, further considered the impact of wind direction, wind speed, gradient, and the fuel type to the diffusion of social rumors, this paper puts forward three basic situations of rumor's spread, they are acceleration, deceleration, and repeated shocks. Finally, the paper further proposes five major guiding principles in social rumors' governance, include that the rumors will stop in the nick of time, the trust of public, the policy of persuasion, the literacy of people, and the rule of law.