The disclosure belongs to the technical field of microelectronic devices and memories, and discloses a three-dimensional stacked phase change memory and a preparation method thereof. The preparation method includes: preparing a multilayer structure in which horizontal electrode layers and insulating layers are alternately stacked, then performing etching to form trenches and separated three-dimensional strip electrodes, next filling the trenches with an insulating medium, and then forming small holes at the boundary region between the three-dimensional strip electrodes and the insulating medium, thereafter sequentially depositing a phase change material on the walls of the small holes, and filling the small holes with an electrode material to prepare vertical electrodes, so as to obtain a three-dimensional stacked phase change memory stacked in multiple layers. By improving the overall process of the preparation method, the disclosure realizes the establishment of a three-dimensional phase change memory array by using a vertical electrode structure.