The government’s environmental governance discourse, with its dominant position in the construction of environmental issues in China and also its vital role in communication, mobilization, education and consensus building, have comprehensively led the discourse pattern of environmental communication and exerted a profound impact on the implementation and effect of environmental governance. This paper, from the perspective of historical study approach and discursive institutionlism paradigm, explores the evolution characteristics and laws of the government’s environmental governance discourse since the establishment of People’s Republic of China, thus supplies the insufficiency on governance discourse research in the field of environmental communication. From the vertical perspective of historical development, the government’s environmental governance discourse presents four distinct phase characteristics; from the horizontal perspective of discourse category, the strategic discourse, management discourse and public participation discourse of the government’s environmental governance have undergone tremendous changes as well. Generally speaking, the change of the Chinese government’s environmental governance discourse since the establishment of People’s Republic of China has shown the main characteristics of putting more emphasis on economy than environmental protection, driving by the government’s internal reform and searching for external consensus continuously and extensively.