A probe generates a shear wave inside a target tissue, and allows the sear wave to pass through regions of interest sending a tracking pulse to the regions of interest through which the shear wave passes. A receiving circuit and beam-forming unit receive echo information of the tracking pulse. A elasticity related result calculation unit calculates shear wave parameters according to the echo information of the tracking pulse, so as to obtain a corresponding elastic measurement result of the regions of interest and a corresponding relationship between the elastic measurement result and statistical variables and generates graphic marks.