The present invention provides a phase-change storage unit for replacing DRAM and FLASH and a manufacturing method thereof, and the phase-change storage unit includes a phase-change material layer and a cylindrical lower electrode being in contact with and located below the phase-change material layer, where the phase-change material layer is formed by connecting a side wall layer and a round bottom layer, forms a hollow cylinder or hollow inverted conical frustum having an opening at an upper part, and the hollow cylinder or hollow inverted conical frustum is internally filled with a medium layer. The present invention adopts the means of preparing a phase-change material layer with a vertical side wall layer and a phase-change material layer with a slant side wall layer, in which a medium material is filled, and adopts the means of a small electrode, so as to reduce the thickness of the phase-change material layer, thereby reducing the phase-change region during the operation, improving the heat stability and the phase-change speed of the phase-change material layer, and finally achieving purposes of reducing the operating power consumption, improving the device data holding capability, increasing the operating speed of the device, and increasing the number of times of cyclic operating of the device.