Abstract: This investigation was designed to approach a novel estimation method of glottal vocal efficiency（GVE） based on conversion function of voice source. The conversion function of voice source was defined the ratio of supraglottal acoustic signals and glottal air volume flow velocity waveforms in frequency domain A carefully designed in vivo canine larynx experiment and several human experiments including different vowels, pressed, falsetto, breath and typical laryngeal diseases were adopted to analysis this alternative GVE method. Compared with other vocal efficiency, it is shown that this method could eliminate the contribution from the super vocal tract transmission and resonance to GVE. and reflect the differences of phonation patterns. The average magnitude of this conversion function in frequency domain represents GVE, and the variation of the magnitude in fundamental frequency is identical to AC/DC value.