Objective To study the characteristics of heart rate variabili ty （HRV） in states of calm supine position

supine position and counting

and ca lm upstanding position

and the relationship with TCM syndromes of cold-h eat and deficiency-excess. Methods Totally 233 patient s diagnosed by TCM & western medicine with different syndromes were divided into five groups. B y comparing the general changes of frequency domain of HRV under three kinds of condition s

the variation of HRV indexes was measured in the excess heat syndrome group （ 64 cases）

deficiency cold syndrome group （16 cases）

cold-heat complex syndrom e group （38 cases）

yin deficiency with fire syndrome group （67 cases）

and defic iency of both yin and yang syndrome group （48 cases）. Results The low frequenc y （LF） and low frequency normalized unit （LFNU） manifested sympathetic nervous a ctivity were augmented and were related with the yang syndrome and heat syndrome obvi ously. The high frequency （HF） and high frequency normalized unit （HFNU） manifes ted parasympathetic nervous activity were augmented and were related with the yi n syn drome and cold syndrome. The increased LF/HF reflected the yang syndrome and hea t syndrome. The decreased LF/HF reflected yin syndrome and cold syndrome. The co ndition of counting had a weighing influence on the diagnosis of yang syndrome a nd heat syndrome. And the condition of upstanding played a weighing role in defi ciency syndrome and cold syndrome. Conclusion The law o f changes of HRV under three kinds of condition is helpful in syndrome differentiation of cold-heat an d deficiency-excess.