Objective To explore the high-risk factors and analyze the clinical characteristics of massive pulmonary hemorrhage (MPH) in infants with extremely low birth weight (ELBW). Methods Two hundred and eleven ELBW infants were included in this study. Thirty-five ELBW infants who were diagnosed with MPH were labelled as the MPH group, and 176 ELBW infants without pulmonary hemorrhage were labelled as the control group. The differences in clinical characteristics, mortality rate, and incidence of complications between the two groups were analysed. The high-risk factors for MPH were identified by multiple logistic regression analysis. Results The MPH group had significantly lower gestational age, birth weight, and 5-minute Apgar score than the control group (P < 0.05). The MPH group had significantly higher rates of neonatal respiratory distress syndrome, patent ductus arteriosus (PDA), early-onset sepsis (EOS), intracranial hemorrhage, pulmonary surfactant utilization, and death compared with the control group (P < 0.01). The multiple logistic regression analysis showed that 5-minute Apgar score was a protective factor for MPH (OR=0.666, P < 0.05), and that PDA and EOS were risk factors for MPH (OR=3.717, 3.276 respectively; P < 0.01). In the infants who were discharged normally, the MPH group had a longer duration of auxiliary ventilation and a higher incidence rate of ventilator-associated pneumonia (VAP) compared with the control group (P < 0.05). Conclusions A higher 5-minute Apgar score is associated a decreased risk for MPH, and the prensence of PDA or EOS is associated an increased risk for MPH in ELBW infants. ELBW infants with MPH have a prolonged mechanical ventilation, a higher mortality, and higher incidence rates of VAP and intracranial hemorrhage compared with those without pulmonary hemorrhage.