This article is based on a study of the development process of Acoustic Space and Visual Space in order to clarify the spatial morphology, which is proposed by McLuhan, as well as refreshes the understanding of McLuhan’s media thoughts. McLuhan’s interest on space was triggered by his early study on literary environment. With the influence of Innis et al, McLuhan took a new approach toward space in putting forward the Acoustic Space and Visual Space, from which other spatial morphology derive. He insisted on subdividing and refining above-mentioned spaces until his twilight of life for the sake of exploring the mechanism and evolution. This article elucidates the knowledge tradition, on which media thoughts rely, was rooted in the grammar tradition that implied by the medieval trivium. Thus, both Acoustic Space and Visual Space are metaphorical concepts based on the analogies of experience.