Abstract: The frequency analysis of Heart Rate Variability (HRV) can singly reflect the activity of sympathetic or parasympathetic nerve. HF is affected only by parasympathetic activity and LF mainly by sympathetic activity. The index plays a important role in the diagnosis of mental-somatic disease such as hypertension and coronary heart disease et al, also can be used to distinguish automatic nerve reactivity mode of different emotions. It is anticipated to diagnose different emotion disorders as a physiological indicator

Key words: heart rate variability, automatic nerve reactivity mode, diagnosis of emotion disorders