The invention relates to a method for measuring an ultrasonic attenuation parameter, guided by harmonic elastography, and comprising a step of application, using a vibrator contained in a probe in contact with a viscoelastic medium, of a continuous low-frequency vibration, said continuous low-frequency vibration generating an elastic wave inside the viscoelastic medium, and generation (CW), during propagation of the elastic wave and using an ultrasonic transducer in contact with the viscoelastic medium, of a series of ultrasound acquisitions, said series of ultrasound acquisitions comprising groups of ultrasound acquisitions, which groups of ultrasound acquisitions are generated at a repetition rate, wherein each group of ultrasound acquisitions comprises at least one acquisition； the ultrasonic attenuation parameter is measured on the basis of the ultrasound acquisitions obtained during the application of the continuous low-frequency vibration.
