Hepatic dysfunction is often observed in patients with Graves’ hyperthyroidism. The aims of this study were to investigate the risk factors for hepatic dysfunction and to analyze the efficacy of 131I (radioactive iodine-131) treatment. In total, 2385 patients with Graves’ hyperthyroidism (478 males, 1907 females; age 42.8 ± 13.5 years) were involved in our study. Of these, 1552 cases with hepatic dysfunction received 131I treatment. All clinical data were retrospectively reviewed to explore the risk factors associated with hepatic dysfunction using logistic regression analysis. Furthermore, we observed thyroid and liver function indices for the 1552 subjects at 3, 6 and 12 months after 131I treatment, in order to evaluate efficacy. Overall, 65% patients were affected by hepatic dysfunction. The most common abnormality was elevated alkaline phosphatase (ALP), of which the prevalence was 52.3%. The percentages of hepatocellular injury type, bile stasis, and mixed type were 45.8%, 32.4%, and 21.8%, respectively. Both univariate and multivariate analyses demonstrated that age, duration of Graves hyperthyroidism, free triiodothyronine (FT3)level, and thyrotrophin receptor antibody (TRAb) concentration were the most significant risk factors predicting hepatic dysfunction. Additionally, the patients with mild hepatic dysfunction, or hepatocellular injury type were more likely to attain normal liver function after 131I treatment. Furthermore, after 131I treatment, liver function was more likely to return to normal in the cured group of patients compared with the uncured group. Older patients and cases with a longer history of Graves’ hyperthyroidism, higher FT3 or TRAb concentration were more likely to be associated with hepatic dysfunction, and the prognosis of hepatic dysfunction was closely associated with the outcomes of Graves’ hyperthyroidism after 131I treatment.