Embodiments for forming a strain image by compensating for displacement in a later direction in an ultrasound system are disclosed. In one embodiment, an ultrasound system includes: an ultrasound data acquisition unit configured to acquire first ultrasound data where compression is not applied to a target object and second ultrasound data where compression is applied to the target object; and a processing unit configured to compensate for displacements in axial and lateral directions in the second ultrasound data based on the first ultrasound data and second ultrasound data, the processing unit being further configured to form a strain image based on the first ultrasound data and the axial and lateral displacement compensated second ultrasound data.