Provided is an ultrasound imaging apparatus. The ultrasound imaging apparatus includes a data acquiring unit transmitting an ultrasound signal to a region of interest (ROI) of an object and then receiving an ultrasound echo signal reflected from the ROI of the object, and a control unit calculating a shear modulus of at least one point in the ROI and a strain of the at least one point, based on the received ultrasound echo signal, and calculating a stress applied to the at least one point by using the shear modulus and the strain.
