The invention discloses a self-gating resistance-variable memory unit and a preparation method thereof and belongs to the technical field of memories. The self-gating resistance-variable memory unit comprises a stack structure, a vertical trench, an M8XY6 gating layer, a resistance
transition layer and upper conductive electrodes, wherein the stack structure contains a plurality of
layers of lower conductive electrodes; the vertical trench is formed by
etching the stack structure; the M8XY6 gating layer is formed on the inner wall of the vertical trench and at the bottom of the vertical trench; the resistance
transition layer is formed on the surface of the M8XY6 gating layer; the upper conductive electrodes are formed on the surface of the resistance
transition layer and the vertical trench is filled with the upper conductive electrodes. The self-gating resistance-variable memory unit and the preparation method thereof have the benefits that based on a resistance-variable memory with a self-gating function taken as the memory unit, a self selection function can be realized by means of the features of nonlinear variation of own resistance of the memory unit along with
voltage without relying on a gated
transistor and a
diode; the structure is simple, the integration is easy, the density is high, the cost is low, and the reading
crosstalk phenomenon in a cross array structure can be restrained; meanwhile, the self-gating resistance variable memory unit is suitable for a plane stack cross array structure and a vertical cross array structure, and high-density three-dimensional memory can be realized.