A method of generating an ultrasound image includes transmitting an ultrasound signal to a predetermined point included in an object and receiving at least three response signals reflected from the predetermined point； extracting a plurality of response signal pairs by combining the received at least three response signals two-by-two； obtaining a plurality of pieces of prediction vector information, each of the pieces of prediction vector information indicating a prediction velocity magnitude and a prediction velocity direction of the predetermined point, based on reception angles and Doppler frequencies of the response signals included in the plurality of response signal pairs； and determining vector information indicating a velocity magnitude and a velocity direction of the predetermined point, based on the plurality of pieces of prediction vector information.
