Objective To explore the clinical value of the serum β-HCG detection in 131I treatment of patients of child-bearing age with hyperthyroidism. Methods The clinical data and serum β-HCG, FT3, FT4, TSH and TRAb levels of 420 female patients of child-bearing age with hyperthyroidism were retrospectively analyzed. Results The results showed that the incidence pregnancy with hyperthyroidism was 5.7%. There was no significantly difference on incidence of pregnancy among the women patients aged 18 ~ 35 with hyperthyroidism. There was a significant difference in the incidence of pregnancy between the group aged 36~40 and the group aged 18~35 of female patients with hyperthyroidism. The serum β-HCG levels in menstrual reduction, menstrual disorder or amenorrhea group were significantly higher than normal menstruation group (P <0.01). There were significant differences in thyroid hormone levels of FT3, FT4, TSH and TRAb between normal menstruation group and reduced menstruation, disordered menstruation or amenorrhea group. The research shows that the patients of child-bearing age with hyperthyroidism were more likely in pregnancy when they were in menstrual reduction, menstrual disorder or amenorrhea period. Conclusion Patients of child-bearing age with hyperthyroidism should carry out the routine detection of serum β -HCG before they have 131I treatment, in order to prevent missed diagnosis of early pregnancy.