Objective To explore the constituents of symptom clusters, and identify the influencing factors in pregnant women in the third trimester, and to provide references for symptom management in late gestation. Methods A total of 223 pregnant women in the third trimester were enrolled and asked to fill the Memorial Symptom Assessment Scale. Exploratory factor analysis was applied to identify symptom clusters, and multiple linear regression analysis was used to determine the factors affecting symptom clusters. Results The five most common symptoms in pregnant women in the third trimester were nocturnal urination (93.7%), difficulty sleeping (66.4%), leg cramp (64.1%), shortness of breath (58.7%) and sweats (56.1%).Four symptom clusters were identified,including body image disorder symptom cluster,activity intolerance symptom cluster, intestinal related symptom cluster, and sleep related symptom cluster.Age, gestational weeks, BMI and physical exercise level before pregnancy were predictive factors for the occurrence of symptom clusters （P＜0.05，P＜0.01）. Conclusion Pregnant women in the third trimester experience many symptoms, which act in concert with each other and appear in the form of symptom clusters.It is suggested that health care professionals should comprehensively assess the discomfort symptoms of pregnant women in the third trimester, and provide symptom-cluster-based symptom management in late gestation.