Knowledge diffusion has become an important research topic in bibliometrics. Existing results pay more attention to studying the knowledge diffusion in one discipline or among different fields, while studies on the dynamic process of the academic innovation diffusion remain rare. Present study provides a valuable reference not only for colleges and universities to construct the disciplines, organize the interdisciplinary research, tackle the key problems, select the research topics, grasp the subject frontier and trend, but also important for the scientific research management departments to plan strategy and policy, and evaluate projects and research. This study establishes a sequential network of knowledge diffusion, draws the diffusion curve, and measures the speed and acceleration. The subject distribution as well as the delay and diffusion curved in different subjects have been studied. Besides, the diffusion strength and the information interactive mode have been analyzed. This paper also identifies the main path, the main path component, and the key nodes with the definition of the diffusion span, the diffusion speed, the diffusion acceleration, the diffusion strength and the diffusion delay. This paper integrates different methods and analysis dimensions, and finally concludes the general methods and steps to analyze the diffusion process.