McLuhan (1964) noted "medium is message" and medium is extension of human boy in his book < Understanding Media: The Extensions of Man>. This book supported an outstanding understanding of medium at that age, although the view exit one-sidedness leading to technologic determinism. Bimber (1990) distinguished three interpretations of technological determinism: The Normative, Nomological and Unintended Consequences accounts to define the technologic determinism through relative literatures. In this essay, the introduction of technologic determinism force on McLuhan and Bimber's idea. The second part will argue their idea and the example the supported in their literatures. In third section, Vygotsky's double-stimulation and high-order-thinking (including culture-historical activity theory), and also, the actor-network theory (ANT) will supply to understand what's medium. Finally, the essay will consider the question: what's education.