OBJECTIVE： To observe the effects of recombinant human interferon （IFN） α1b on thyroid function of patients with chronic hepatitis C （CHC）. METHODS：Retrospective collection 90 CHC patients， according to whether to merge with hyperthyroidism into hypothyroidism group， hypothyroidism group and CHC group，30 cases in each group. 3 groups were given IFN-α1b 40 μg， qod， combined with ribavirin 0.1 g， tid， for antiviral therapy. Before and after therapy， RVR， EVR， ETVR and SVR were observed in 3 groups， and the levels of T3， T4， FT3， FT4 and TSH were observed in hypothyroidism group， hypothyroidism group before and after antiviral therapy. RESULTS： After treatment， RVR， EVR， ETVR and SVR levels of 3 groups increased significantly，with statistical significance，compared with before treatment（P＜0.05）.After treatment， there was no statistical significance in RVR， EVR， ETVR and SVR among 3 groups， there was no statistical significance （P＞0.05）； there was no statistical significance in the levels of T3， T4， FT3， FT4 and TSH before and after treatment （P＞0.05）. CONCLUSIONS： IFN-α1b combined with ribavirin can obtain good antiviral effect and not worsen existing thyroid disease in the treatment of CHC complicated with thyroid disease.