Seven-year-old child has primary pulmonary hypertension, may be after birth pulmonary vascular resistance did not appear to physiological decline, congenital a combination of factors. Seven-year-old child has primary pulmonary hypertension, may be the fetus after birth, pulmonary vascular resistance did not get normal physiological decline, pulmonary vascular thickness, pulmonary small artery middle layer thickness did not degenerate, the resistance of the pulmonary blood vessels increased, the pulmonary artery pressure will increase. Seven-year-old children have primary pulmonary hypertension, may be a kind of congenital multiple factors together, such as family genetics and other factors caused by. There may be other causes of primary pulmonary hypertension in a seven-year-old child, which, once diagnosed, need to be actively targeted treatment under the guidance of a doctor.