The present invention provides a method and device for detecting a viscoelastic parameter of a viscoelastic medium. The method comprises: applying a mechanical vibration at a single predetermined frequency to the viscoelastic medium to generate a shear wave in the viscoelastic medium (101)； emitting ultrasonic waves to the viscoelastic medium, and receiving ultrasonic echo signals (102)； acquiring maximum displacement data of the shear wave at various depths according to the ultrasonic echo signals (103), each of the maximum displacement data representing a maximum oscillation amplitude of the shear wave when the shear wave propagates to different depths in the viscoelastic medium； fitting each of the maximum displacement data to obtain a maximum displacement attenuation curve (104)； and determining the viscoelastic parameter of the viscoelastic medium according to the maximum displacement attenuation curve (105). Thus, a viscoelastic parameter related to both elasticity and viscosity can be acquired to increase a measurement dimension of a tissue, facilitating the provision of richer tissue parameter information and measurement dimensions, and providing a more accurate measurement result of tissue fibrosis.
