〔Abstract〕 Objective To analyze the pregnancy outcome of twins in infertile women with polycystic ovary syndrome(PCOS) after the frozen-embryo transfer. Methods Retrospective analysis was made on 1449 patients who received in vitro fertilization-frozen embryo transfer and obtained twin pregnancy. The PCOS group was 421 patients with infertility caused by polycystic ovary syndrome, and the control group was 1028 patients with infertility caused by fallopian tube factors alone in the same period.The two groups of patients were further respectively divided into non-overweight group(BMI<24 kg/m2) and overweight group(BMI≥24 kg/m2),which were recorded as: non-overweight PCOS group, overweight PCOS group; non-overweight control group, overweight control group. General information, pregnancy complications, and neonatal outcomes of non-overweight PCOS group and non-overweight control group were compared, which were also compared between the overweight PCOS group and the overweight control group. Results The abortion rate and late abortion rate in non-overweight PCOS group were higher than those in the non-overweight control group(P<0.05). There was no significant difference in early abortion rate, premature delivery rate, morbidity of hypertensive disorders of pregnancy(HDP)、gestational diabetes mellitus(GDM), cesarean section rate, average weight and malformation rate of newborn between the two groups. The mean neonatal birth weight in overweight PCOS group was lower than that in overweight control group;abortion rate and late abortion rate in PCOS group were higher than those in overweight control group(P<0.05).There was no significant difference in early abortion rate, premature delivery rate, morbidity of HDP、GDM, cesarean section rate and neonatal malformation rate between the two groups. Conclusion PCOS after frozen-embryo transfer increase the pregnancy abortion rate and late abortion rate of twins, and PCOS in overweight patients reduce the neonatal birth weight.