Objective: To analyze the value of serum irisin in the diagnosis of hypothyroidism during pregnancy so as to provide the basis for the diagnosis and screening of hypothyroidism in pregnancy. Methods: A total of 120 patients with hypothyroidism during pregnancy were selected as a case group, and 100 healthy pregnant women who had received prenatal examination in the same period were selected as a control group. The general information and the serum levels of thyroid stimulating hormone (TSH), free thyroxine (FT4), thyroid peroxidase antibody (TPO-Ab), irisin in the two groups were detected, and the diagnostic values of serum indexes in hypothyroidism during pregnancy were analyzed by receiver operating characteristic (ROC) curve. Results: The body mass index (BMI) level and the serum TSH, TPO-Ab, irisin levels of the patients in the case group were higher than those in the control group, and the differences between the two groups were statistically significant (P<0.05). The results of logistic multiple regression model analysis showed that the occurrence of hypothyroidism during pregnancy was correlated with serum TSH and irisin levels (P<0.05). The area under ROC curve (AUC) of serum TSH and irisin levels in the diagnosis of hypothyroidism during pregnancy was 0.812 and 0.735, respectively (P<0.05), and the sensitivity and specificity were 0.900, 0.608 and 0.610, 0.810, respectively at the cut-off value. When the two indicators were jointly detected, AUC was increased to 0.928 (P<0.05), and the sensitivity and specificity were 0.792 and 1.000, respectively at the cut-off value. Conclusion: The increase of serum irisin level during pregnancy has certain diagnostic value for patients with hypothyroidism. The combined detection of serum irisin and the routine indexes such as TSH can improve the effects on screening and diagnosis of hypothyroidism during pregnancy.