Objective To explore factors associated with postpartum depression among mothers of preterm babies in neonatal intensive care unit（NICU）, so as to provide direction for prevention and decrease the incidence of postpartum depression.

Methods Totally 210 mothers of preterm infants treated in NICU from January 2019 to December 2020 were recruited. Based on the score of Edinburgh Postpartum Depression Scale, they were divided into depression group （58 cases） and non depression group （152 cases）. Self-made questionnaire was used to collect clinical data of preterm infants and their mothers. Univariate chi square test and multivariate binary logistic regression were used to screen the risk factors of postpartum depression among mothers of preterm babies treating in NICU.

Results Univariate analysis showed that gestational age, use of invasive mechanical ventilation, prognosis of preterm infant, education level, family monthly income, pregnancy complications, primipara, timely antenatal care, hospital satisfaction, mother-in-law and daughter-in-law relationship, and husband-wife relationship were statistically different between 2 groups（all P < 0.05）. Logistic regression analysis showed that the risk factors of postpartum depression among mothers of preterm infants in NICU were short gestational age （OR = 7.258, 95% CI： 3.215-16.389）, invasive mechanical ventilation （OR=2.931, 95% CI： 1.056-8.136）, poor prognosis of preterm infants （OR=13.498, 95% CI： 4.414-41.275）, and the protective factor was timely antenatal care （OR=0.337,95% CI：0.116-0.982）.

Conclusion Several risk factors are associated with postpartum depression among mothers of preterm infant in NICU. Based on the clinical risk and protective factors, targeted intervention measures should be taken to reduce the incidence of postpartum depression of these mothers.