Neonatal pneumonia is a common disease in newborns. Early respiratory symptoms and signs are not obvious, especially in premature infants, making early diagnosis difficult and an important cause of neonatal death. Neonatal pneumonia can be divided into infectious pneumonia and aspiration pneumonia by nature, and can occur in utero, during delivery, or after birth. 1, intrauterine infectious pneumonia: intrauterine infectious pneumonia is transmitted through the amniotic fluid or bloodstream. The causes are as follows: (1) inhalation of contaminated amniotic fluid: newborn mothers infected with bacteria, viruses, and protozoa during pregnancy, premature rupture of the amniotic membrane for more than 24 hours or chorioamnionitis contaminating the amniotic fluid, the incidence of infection is as high as 50% to 80% or more. Bacteria (such as Escherichia coli, Klebsiella, Listeria, Group B Streptococcus, Staphylococcus aureus) and fungi, viruses, mycoplasma, and chlamydia in the vagina of the pregnant mother infect the amnion upstream, and the fetus inhales the contaminated amniotic fluid and develops pneumonia. The causative factors are preterm labor, stalled labor, and excessive vaginal fingering. (2) Blood-borne transmission to the lungs: The mother may be asymptomatic when she is infected with viruses, protozoa, mycoplasma and syphilis spirochetes in the second trimester, but the pathogens may pass through the placental barrier and be transmitted to the fetus via blood-borne transmission, causing the fetus to develop systemic multi-organ infections such as brain, liver, spleen and lung. 2. Infectious pneumonia during delivery: the pathogenic microorganisms are similar to pneumonia caused by intrauterine inhalation of contaminated amniotic fluid, and bacterial infections are more common with gram-negative bacilli, in addition to group B streptococci, Chlamydia trachomatis, CMV, HSV and other viruses. 3, postnatal infectious pneumonia: postnatal infectious pneumonia has the highest incidence and is transmitted as follows: (1) contact transmission: if the person in contact with the infant has a respiratory infection, it is easily transmitted to the newborn, resulting in pneumonia in the newborn. (2) Blood-borne transmission: In cases of umbilical cord infection, skin infection and sepsis, the pathogens are transmitted to the lungs via blood, leading to pneumonia, and the pathogens of pneumonia can also enter the bloodstream, causing sepsis.