Abstract: A method and an apparatus for detecting yin-yang and asthenia-sthenia by means of the heart rate variability (HRV) analysis, which is originally difficult to be determined and utilized, are revealed, so as to help the clinical diagnoses of the Western and the Chinese physicians. The detecting method comprises the steps of (1) capturing an electrocardiogram signal from a person; (2) converting the electrocardiogram signal into a heart rate power spectral density; (3) computing a low frequency power and a high frequency power of the heart rate power spectral density; (4) calculating a yin parameter and a yang parameter based on the low frequency power and high frequency power; and (5) calculating the standard scores of the yin parameter and the yang parameter to be a yin index and a yang index respectively for determining the yin-yang and asthenia-sthenia for the person.