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.