Objective To compare the effects of propylthiouracil and methimazole on the pregnancy outcome of patients with hyperthyroidism (hyperthyroidism) during pregnancy. Methods A retrospective analysis of the clinical data of 102 patients with hyperthyroidism during pregnancy admitted to the People's Hospital of Lianshan Zhuang and Yao Autonomous County in Guangdong Province from January 2017 to December 2020. Among them, 51 cases received propylthiouracil (PTU) treatment as PTU group, and the other 51 cases received methimazole (MMI) treatment as MMI group. After treatment, the levels of thyroxine [thyroid stimulating hormone (TSH), thyroxine (T4),free thyroxine (FT4)], pregnancy outcome and maternal adverse reactions were compared between the two groups.Results After treatment, the level of TSH in the PTU group was significantly higher than that of the MMI group, and T4 and FT4 were significantly lower than the MMI group. The difference between the two groups was statistically significant (P＜0.05); the PTU group experienced premature delivery, miscarriage, neonatal fetal distress, and fetal distress in the PTU group. The incidence of hyperthyroidism was significantly lower than that of the MMI group, and the rate of full-term delivery was higher than that of the MMI group, and the differences were statistically significant (P＜0.05); the total incidence of adverse reactions such as skin pruritus, pregnancy- induced hypertension, and neutropenia in the PTU group was Significantly lower than the MMI group, and the difference was statistically significant (P＜0.05). Conclusion Propylthiouracil is more helpful than methimazole in the improvement of thyroid function and pregnancy outcome in patients with hyperthyroidism during pregnancy, and it is safer.