Abstract: Objective To investigate the difference of the complications between hemodynamic significant patent ductus arteriosus(HsPDA) and non-hemodynamic PDA(nHsPDA) in premature infants, and the complications of HsPDA in different diameter groups. Methods Using the method of retrospective analysis, 71 premature infants with PDA hospitalized in NICU of the First Affiliated Hospital of University of science and technology of China from January 2017 to December 2018 were divided into HsPDA group and nHsPDA group according to the hemodynamic changes. Among them, HSPDA group was divided into large, medium and small groups according to the diameter of the ductus arteriosus. Data were analyzed using Fisher test for independence in a contingency table and t-test. Results There were 20 cases in nHsPDA group and 51 cases in HsPDA group, which included 15 cases in large HsPDA group(>3 mm), 34 cases in medium HsPDA group(1.5-3.0 mm), and 2 cases in small HsPDA group(<1.5 mm). There was significant difference in the diameter of ductus arteriosus between HsPDA group [(2.67±0.97) mm] and nHsPDA [(1.77±0.75) mm, P<0.001]. There was no significant difference in gender, age distribution, body weight, Apgar score, multiple births and intervention(PS, mechanical ventilation) between HsPDA group and nHsPDA group(all P>0.05). There was no significant difference in the incidence of complications between HsPDA group and nHsPDA group(P>0.05). There was no significant difference in the incidence of complications between the large, medium and small HsPDA groups(P>0.05), but the incidence of ROP(7/15, 46.67%) and IVH(4/15, 26.67%) in the large HsPDA group were higher than those in the small and medium HsPDA group. There was no significant effect of different diameter on closure of ductus arteriosus before discharge of HsPDA. Conclusion The average diameter of ductus arteriosus in HsPDA group is larger than that in nHsPDA group, but there is no significant effect on complications. There is no significant effect on complications of HsPDA with different diameter of ductus arteriosus. Patients with PDA should be treated with conservative support, and drug or surgical closure should be used if necessary.