A Cu-doped Sb2Te3 system phase change material, a phase change memory, and a preparation method thereof belonging to the technical field of micro-nano electronics are provided. A Sb—Te system phase change material is doped with Cu element to form Cu3Te2 bonds with both tetrahedral and octahedral structures in the case of local enrichment of Cu. The strongly bonded tetrahedral structure improves the amorphous stability and data retention capability of the Sb—Te system phase change material, and the octahedral structure of the crystal configuration improves the crystallization speed of the Sb—Te system phase change material. A phase change memory including the phase change material and a preparation method of the phase change material are also provided. Through the phase change material provided by the invention, both the speed and amorphous stability of the device are improved, and the comprehensive performance of the phase change memory is also enhanced.