Objective:To investigate the correlation between histologic chorioamnionitis(HCA) and periventricular leukomalacia(PVL) in preterm infants less than 34 weeks old.Methods:A total of 287 preterm infants born in Qingdao Women′s and Children′s Hospital from January 2018 to December 2018, whose mothers underwent placental pathological examination and preterm infants transferred to the neonatal intensive care unit for treatment, and whose gestational age was less than 34 weeks old, were selected as the study objects. According to the results of placental pathological examination, the infants were divided into two groups: the positive HCA group(167 cases)and the negative HCA group(120 cases). The incidence of PVL was compared between the two groups. According to the results of placental pathological examination and the stage standard of HCA, the preterm infants who had been diagnosed with PVL(41 cases) were divided into three groups: the non-HCA group, the early HCA group and the middle/late HCA group.The severity of PVL, clinical data, complications were compared in each groups, and the conditions that following up to 6 months were adjusted.Results:PVL was 19.16%(32/167) in the positive HCA group and was 7.50%(9/120) in the negative HCA group.There was significant difference in the incidence of PVL between the two groups( P<0.05). Among the preterm infants with PVL, 21.95%(9/41) was in non-HCA group, 31.71%(13/41) was in the early HCA group, and 46.34%(19/41) was in the middle/late HCA group.The severity of PVL, 1 min Apgar score, white blood cell count at 24 h after birth, the incidence of bronchopulmonary dysplasia, the number of hospital stay, the use of antibiotics, the mental development index(MDI) and psychomotor development index(PDI) at the adjusted gestational age to 6 months were significant differences among the three groups( P<0.05). Moreover, the degree of HCA inflammation was positively correlated with the severity of PVL( r s=0.374, P=0.016). Conclusion:There is a correlation between HCA and PVL in premature less than 34 weeks old.With the increasing of HCA inflammation, the incidence and severity of PVL increase. With the progression of the severity of inflammation, the white blood cell count at 24 h after birth, the incidence of bronchopulmonary dysplasia, the use of antibiotics and the time of hospital stay increase, the MDI and PDI scores at the adjusted gestational age to 6 months decrease.