Abstract：It is generally regarded as true that there is a huge gap between modern philosophy and technological praxis .This unreflected belief is accepted by most people,because philosophy always exists as the background of technological praxis and the way that it plays its role is to let itself be overlooked .Only when the technological problems cannot be solved by technological means can the philosophical assumptions behind the technology be reflected on .The distance seems to be farthest between computer science andphilosophy,but the belief hiddenin the science and technologyof computer comes from traditional philosophy,i .e .the representationality of the worldand the dualismof subject and object .When scientists try to figure out why they have failed to solve the problem of knowledge representation,the traditional philosophical assumptions begin to be seriously reflected on and abandoned .Therefore,Martin Heidegger,who had presented us with a thorough critique of traditional philosophy,has been introduced into the area of computer science . The most typical works which apply the insights of Heidegger are ontological design,deictic representation and embodied interaction .Ontological design was put forward by Terry Winograd . Enlightened by another philosopher Hubert Dreyfus,he found that computer science is based entirely on the rationalistic tradition,which claims that the world consists of a set of meaningless facts and these objective facts are independent of any subject .The inevitable slowdown in computer science led Winograd to move away from the unexamined rationalistic orientation and take Heidegger's ontology as the foundation of the new design approach .The practical everyday notions of Heidegger,such as thrownness,readiness-to-hand,breakdown and so on,are all applied in his design approach . The notion of deictic representation is the core of design practice of Philip Agre,and it comes directly from Heidegger's analysis of everyday intentionality .Deictic intentionality corresponds to ready-to-hand and objective intentionality corresponds to present-at-hand .Deictic intentionality implies a deictic ontology,and objective intentionality implies an objective ontology .Classical AI insists on the objective ontology and holds that entities can be defined without reference to any agent's activities .In contrast,Agre holds that each entity should be defined only in indexical and functional terms,in other words,each entity cannot be defined without reference to any agent's activities .Pengi is a program designed to illustrate the notion of deictic representation .Its success not only overcomes toa certain degree the mysteryaround the anti-representationalismof Heidegger,but also demonstrates that the unity of philosophy and technological praxis is possible . Tangible computing and social computing,two current research directions in Human-Computer Interaction ( HCI),are regarded as two different areas of research usually .But according to Paul Dourish,the same idea that underlies each of them is embodiment,i .e .the common way in which human being encounters reality in the everyday world .So tangible computing and social computing are in fact two different aspects of embodied interaction .Though embodied interaction is the future stage of HCI,embodiment is the primary concern of phenomenology .Therefore,designers in HCI can create the approach to embodied interaction depending on phenomenology,especially Heidegger's phenomenology .Moreover,phenomenology can help to provide a common vocabulary and conceptual apparatus,e .g .present-at-hand,ready-to-hand,embodiment,and a set of principles that shape the design of embodied interaction . The Heideggerian approach to the design of computer systems is not at the center of the discourse about computers and their use .But the work described here represents a beginning . With these three pieces of work the philosophy covert in the technological praxis is uncovered gradually,and the relation between philosophy and technology will be closer and opener .The future designer should be both a philosopher and a technical practicer .However,as far as the truth pursued by philosophers is unspeakable and implicit,there should be necessary tensility between philosophy and technology .