Objective To study the heart function,risk factors and associated complications caused by patent ductus arteriosus( PDA)in preterm infants. Methods A retrospective analysis Was conducted at Neonatal Intensive Care Unit of Shenzhen People＇s Hospital from October 2016 to August 2017 to study the cardiac functions of infants less than 3 days after birth betWeen PDA group and non－PDA group(1: 1 paired study according to gestational age and Weight). MeanWhile their clinical data Were collected by case－control analysis method,to explore the risk factors and complications caused by PDA in preterm infants. Results There Were 50 cases in PDA group,and 50 cases in non－PDA group. The physical data betWeen 2 groups had no statistically significant difference(all P＞0. 05). The heart rate (HR),cardiac output(CO)and cardiac output index(CI)in 2 groups Were(148. 36 ± 12. 98)times／min,(0. 52 ± 0. 21)L／min,(0. 44 ± 0. 19)L／( min·m2 )and(142. 52 ± 18. 07)times／min,(3. 48 ± 0. 92)L／min,(2. 99 ± 0. 80)L／(min·m2 ),respectively;the levels of PDA group Were higher than those of the non－PDA group,and the differences Were significant(P﹦0. 021,0. 020,0. 027). Single factor analysis shoWed that PDA in the preterm infants Was significantly associated With asphyxia,premature rupture of membranes and the use of prenatal hormone( P﹦0. 001,0. 009,0. 004). Ventilation time,pneumonia,feeding intolerance,and bronchial pulmonary dysplasia Were asso﹣ciated With PDA in preterm infants(P﹦0. 010,0. 010,0. 000,0. 026). The Logistic regression analysis shoWed that asphyxia Was independent risk factor for PDA in preterm infants(OR﹦7. 280),and prenatal antenatal corticosteroids Was independent protective factor( OR ﹦0. 008). Conclusions In preterm infants With PDA,the HR,CO and CI increase and electronic heart monitoring could identify the hemodynamic changes in preterm infants With PDA. Asphyxia is major high risk factor in PDA in preterm infants,While the use of prenatal antenatal corticosteroids is seen as the pro﹣tective factor. PDA in preterm infants can prolong the ventilation times and increase the pneumonia,feeding intolerance and BPD.