Abstract: Attachment researchers investigated the neurophysiological mechanism of human attachment based on neurobiology studies of animal social attachment. They made a conclusion that the insecure individuals have higher heart rate and high cortisol comparing with the secure ones , While the location of brain function and electrophysiological study shows that compared to secure infants, insecure infants exhibited less left frontal brain activities when attachment system was inactivated, but there are no consistent results in adults. However, the researches are mostly correlational ones and can not provide causal inferences, moreover, the further researches about basic physiological characteristic of attachment need to be reinforced and discovered

Key words: attachment, autonomic nervous system, hypothalamic-pituitary-Adrenal, brain