Stability is one of the most important criterions to judge the quality of products, especially for the phase-change memory (PCM), which is regarded as the most promising candidate for next-generation non-volatile memory. Due to the lack of resistance stability, read errors can occur easily and the reliability of PCM will be influenced. Using Sb₂Te as a base material, the resistance stability of Sb₂Te was studied, and the results indicated that in the whole cooling process, the resistance of Sb₂Te crystalline film was extremely steady under different annealing temperatures and different cooling rates. To unravel the reason why the resistance of Sb₂Te crystalline film has good stability, further study was carried out and the results showed that there was no new diffraction peak in the XRD pattern, and the HRTEM images showed the similar hexagonal phase for the films under different annealing temperatures. Moreover, it was observed that the resistance in Sb₂Te-based PCM device was still stable for crystalline state and amorphous state. These results revealed that the stability of Sb₂Te crystalline films at a micro level and the stability of microscopic structure resulted in the stability of resistance. Therefore, based on the present study, the stability of phase-change material Sb₂Te can be applied to exploit more reliable PCM for near-future application.