An automatic breastfeeding method of a premature infant is disclosed, which includes a preparation stage, an active lactation stage, a passive lactation stage and a rest stage. The invention also provides an automatic breastfeeding machine used for the automatic breastfeeding method of a premature infant, comprising a stomach tube, a lactation supply device, a detector and a control device. According to the invention, a self-sucking ability of the premature infant is trained, normal circulation of a mouth-pharyngeal-gastric-intestinal reflex of the premature infant is realized, and nutritional requirements of the premature infant are ensured in the case of taking differences of the premature infants into account, so that the premature infants have no difference with term infants in care, diet, neurological development and growth and development in the future.