This research took knowledge life cycle as a theoretical basis, and chose Journal of International Communication, Journalism Quarterly, Journalism & Communication, and Modern Communication as study samples. Based on the analysis of the literature, researchers, research institutions, research keywords etc., the authors draw a panoramic description of the life cycle and operating mechanism of mainland journalism and communication studies.In the time dimension, mainland journalism and communication studies show clear develop context in both knowledge flows and knowledge structures. The main motivation of knowledge intergeneration is the change of communication environment. The change path of study issues is not unidirectional transferred nor circulating rebirthed, but the reticular structure with outward extension of the breadth and depth of research. In the spatial dimension, we gave a comprehensive description of academic power map, and conducted a descriptive study of researchers, research institutions, and the partnership between different samples. The main motivation of academic power map is empowering behaviors between researchers and cooperation among research institutions.