The increase of neonatal leukocytes is divided into physiological increase and pathological increase, as follows: First, physiological increase, the number of newborn leukocytes is higher than normal, just after birth, the number of leukocytes is around (15-20) × 10^9, with the growth of the day, the number of leukocytes gradually return to normal, this situation does not need to be dealt with. Second, pathological increase, the most common cause of pathological increase is infection, and some rare leukemia. Common infections include intrauterine infections, umbilical cord infections, and lung infections; serious ones include systemic infections such as sepsis and septic meningitis. Common symptoms include poor response, poor milk intake, fever or temperature not rising, and in severe cases, apnea, cyanosis, and convulsions. Pathological infections require hospitalization, complete blood cultures, and lumbar puncture if necessary. The main treatment is anti-infection therapy.