Abstract: The present invention provides a high-speed, high-density, and low-power consumption phase-change memory unit, and a preparation method thereof In the preparation method of the present invention, a transition material layer with an accommodation space is first prepared on a surface of a structure of a formed first electrode, where the accommodation space corresponds to the first electrode; a phase-change material layer is then prepared on a structure of the formed transition material layer, and the phase-change material layer is enabled to be in the accommodation space; and afterwards, a second electrode material layer is prepared on a surface of a structure of the prepared phase-change material layer, so as to prepare a phase-change memory unit; where phase-change material layer and the first electrode are isolated from each other by the transition material layer, and the second electrode material layer is in electrical communication with the phase-change material layer.