Resistive memory unit preparing method

The invention provides a resistive memory unit preparing method, and relates to the technical field of non-volatile memory devices. The preparing method comprises the steps that a lower electrode layer is formed on a substrate through a conductive material; an insulating dielectric layer is deposited or spin-coated on the lower electrode layer; a trench is formed on the insulating dielectric layer through a photolithography process, and the bottom of the trench extends to the lower electrode layer; a function layer of a resistive memory unit is formed within the trench; the function layer is in an upper and lower layer laminated structure, and is formed by laminating an amorphous SnOx layer and a nitrogen oxide MnOxNy layer; the range of x in the amorphous SnOx is between 0 and 2; the range of x and the range of y in the nitrogen oxide MnOxNy are respectively between 1 and 2 and between 0.001 and 2; an upper electrode layer is formed on the function layer through a conductive material; and through a flattening process, the upper electrode layer is flush with the surface of the insulating dielectric layer. According to the resistive memory unit provided by the invention, stable multi-value memory is realized, and the memory density and stability of the memory unit can be improved.