Embodiments for spatially compounding ultrasound images for removing seam artifact in an ultrasound system are disclosed. In one embodiment, the ultrasound system includes: an ultrasound data acquisition unit configured to transmit ultrasound beams to a target object, receive ultrasound echoes reflected from the target object and provide a plurality of ultrasound frame data sets for a plurality of frames, said plurality of ultrasound frame data being acquired at different steering angles of scan lines； and a processing unit configured to form a plurality of ultrasound images and form a plurality of mask images corresponding to the respective ultrasound images based on the plurality of ultrasound frame data sets for removing seam artifact and spatially compound the plurality of ultrasound image based on the plurality of mask images to form an ultrasound spatial compound image.
