〔Abstract〕 Objective To investigate the interleukin-1β(IL-1β) induced apoptosis of thyroid cells in Hashimoto thyroiditis(HT) and its potential mechanism. Methods ① Factor associated suicide(Fas) mRNA expression in FRTL-5 cells were detected by real-time PCR under different concentration and reacting time of IL-1β.②The control group, IL-1β group, IL-1β+caspase8 inhibitor(Z-IETD-FMK) group were set up, and the apoptosis rate of each group was analysed by flow cytometry. Results ① The result of real-time PCR showed that there was a dose-time dependent relationship between IL-1β and Fas mRNA expression levels of FRTL-5 cells(P<0.05); ②Flow cytometry results showed that compared with the control group, the apoptosis rate of thyroid cells increased after IL-1β induction(P<0.05) and the increase of IL-1β-induced thyroid cell apoptosis was inhibited after combined with Z-IETD-FMK(P<0.05). Conclusion IL-1β may induce apoptosis of thyroid cells through Fas and caspase 8 pathways.