Abstract: Attachment theory focuses mainly on attachments formed between infants and their fosters.Infants who learn from the reactions of their fosters develop a type of inner working mode for themselves and others,which forms the basis of an individual's interpersonal relationship.It has significant influence for the individual's emotional and behavioral reaction.This paper took a case to demonstrate the basic concept of attachment theory and its use in understanding and directing in therapies.By this case the writer explained the relationship between attachment theory and clinical symptoms,and showed mental state,reflection and mirroring function in psychodynamic therapy.

Key words: attachment theory, internal working model, psychodynamic therapy