The purpose of Heidegger in Kant and the Problem of Metaphysics is affording a historical introduction of his fundamental-ontology through his interpretation of Kant by three stages. In the third stage, the Laying of the Ground for Metaphysics in Its Originality, Heidegger interprets Kant by the phenomenological way through succeeding and applying Husserl's phenomenological theory of time when he is founding the transcendental power of imagination as the basis and relating it to the finitude in human being. Compared to Husserl, it can be found that there are two points in this succession, the width of time and the division of time into three levels.The succession of these two points, especially the latter, is the basis and the key to Heidegger's phenomenological interpretation of Kant.