One of the main themes in Heidegger’s thought is the genesis of metaphysics. This matter plays a significant role in the fundamental question in the so-called Turn period. In this paper, we will concern about three approaches to the genesis of metaphysics in the mentioned period. Heidegger discusses these three approaches in his three different works: Kant and the problem of metaphysics; What is metaphysics? and Plato’s Doctrine of Truth. In Kant and the problem of metaphysics, he indicates a special interpretation of Kant's views according to the notion of "transcendence". In what is metaphysics? Heidegger discusses the issue through the concepts of "nothingness" and "angst", and in Plato’s Doctrine of Truth, he continues the issue via the interpretation of the "Cave Allegory". Although the released times of these three books is so proximate, Heidegger seeks the foundation of metaphysics in them through completely different approaches. In the first and second book, along with Kant’s project, he attempts to find a foundation for metaphysics through the concept of "Dasein". But in the latter book, Heidegger is in the pursuit of transition from metaphysics and calls metaphysics "forgetting of being". He explains that Plato's introducing "Ideas Theory" is an origin of metaphysics and a departure point from being and forgetting it. In this essay, proposing a general approach, we try to explain the mentioned three approaches and their similarities and differences.