Objective To study the application effect of transabdominal amniotic fluid reduction surgery on improving vaginal delivery in the third trimester of pregnancy. Methods A total of 100 patients with polyhydramnios during the third trimester of pregnancy and indications for termination of pregnancy who were treated in Jiangxi Maternal and Child Health Hospital between January 2020 and January 2021 were selected as the study subjects, and they were divided into a study group and a control group according to the random number table method, with 50 cases in each group. Patients in the control group implemented delivery regimen according to the cervical score, and patients in the study group received delivery regimen according to the cervical score after amniotic fluid reduction surgery. Methods of delivery, incidence of perinatal complications, Apgar score of newborn and hospitalization expenses of delivery were compared between the two groups. Results The vaginal delivery rate in the study group was higher than that in the control group, and the cesarean delivery rate was lower than that in the control group, and the difference was statistically significant (P＜0.05). The total incidence of perinatal complications in study group was lower than that in control group, and the difference was statistically significant (P＜0.05). The Apgar score of the study group was higher than that of the control group, and the hospitalization cost of delivery was lower than that of the control group, and the differences were statistically significant (P＜0.05). Conclusion Transabdominal amniotic fluid reduction surgery for patients with polyhydramnios in the third trimester of pregnancy can increase the vaginal delivery rate, reduce the risk of complications and save the cost of hospitalization.