Abstract: In this paper, a novel method was studied to diagnose the vessel disease using the feature of the maximum frequency waveform from the blood flow ultrasound Doppler signals. The sampled audio Doppler flow signals were analyzed using the short time Fourier transform. Then the percentile method was used to obtain the maximum frequency waveform from whose spectrum feature values were extracted to diagnose the vessel disease. From the clinical analysis of Doppler flow signals from the common carotid arteries, it was shown that the method described here gave a higher diagnosis accuracy than the conventional method, the sonogram parameter method.