Abdominal breathing is an effective training method for relaxation.It is applicable for resolving sub-health problems in autonomic nervous malfunction and curing some kinds of psychosomatic disorders.In order to improve its training effect,we develop a kind of abdominal breathing training instrument on the basis of the principle of biofeedback.With both features of biofeedback and breathing training apparatus,it may simultaneously feedback the training effect to the trainer during the abdominal breathing training,and the trainer may regulate his breathing mode for desirable effects.In this paper,the instrument is described in such aspects as the circuit design,composition and clinical application.It is an economical,safe and effective instrument,which can be used in Health Promotion Project.