An ultrasound system, comprising: an ultrasound data acquisition unit including an ultrasound probe having a convex shape, configured to acquire ultrasound data by transmitting and receiving ultrasound signals; and a processing unit in communication with the ultrasound data acquisition unit, the processing unit being configured to set a virtual common point, at which a plurality of scan-lines intersect, in consideration of positions of a plurality of elements in the ultrasound probe having the convex shape, set a plurality of center lines corresponding to a plurality of ultrasound images where each of the plurality of ultrasound images includes a part of an image display area for displaying an ultrasound image and converging into the virtual common point, said plurality of center lines including a first center line and a second center line, set a first plurality of scan lines corresponding to the first center line, move the virtual common point along the second center line to a sub-virtual common point, to set a second plurality of scan lines corresponding to the second center line and converging to the sub-virtual common point, form a plurality of ultrasound images corresponding to the first plurality of scan lines and the second plurality of scan lines, and perform spatial compounding upon the ultrasound images to form an ultrasound spatial compound image, wherein the ultrasound data acquisition unit is configured to acquire the ultrasound data based on the plurality of scan-lines, wherein the number of the plurality of center lines is determined depending on the number of ultrasound images to be compounded, characterised in that the processing unit is configured to: detect an element of the ultrasound probe, through which the second center line passes; detect a center point of the detected element; set a reference scan-line passing through the center point of the element on a basis of the sub-virtual common point corresponding to a reference ultrasound image; set the second plurality of scan-lines based on the reference scan-line and the sub-virtual common point; and rotate the second center line to a third center line to set a third plurality of scan-lines. an ultrasound data acquisition unit including an ultrasound probe having a convex shape, configured to acquire ultrasound data by transmitting and receiving ultrasound signals; and a processing unit in communication with the ultrasound data acquisition unit, the processing unit being configured to set a virtual common point, at which a plurality of scan-lines intersect, in consideration of positions of a plurality of elements in the ultrasound probe having the convex shape, set a plurality of center lines corresponding to a plurality of ultrasound images where each of the plurality of ultrasound images includes a part of an image display area for displaying an ultrasound image and converging into the virtual common point, said plurality of center lines including a first center line and a second center line, set a first plurality of scan lines corresponding to the first center line, move the virtual common point along the second center line to a sub-virtual common point, to set a second plurality of scan lines corresponding to the second center line and converging to the sub-virtual common point, form a plurality of ultrasound images corresponding to the first plurality of scan lines and the second plurality of scan lines, and perform spatial compounding upon the ultrasound images to form an ultrasound spatial compound image, wherein the ultrasound data acquisition unit is configured to acquire the ultrasound data based on the plurality of scan-lines, wherein the number of the plurality of center lines is determined depending on the number of ultrasound images to be compounded, characterised in that the processing unit is configured to: detect an element of the ultrasound probe, through which the second center line passes; detect a center point of the detected element; set a reference scan-line passing through the center point of the element on a basis of the sub-virtual common point corresponding to a reference ultrasound image; set the second plurality of scan-lines based on the reference scan-line and the sub-virtual common point; and rotate the second center line to a third center line to set a third plurality of scan-lines. detect an element of the ultrasound probe, through which the second center line passes; detect a center point of the detected element; set a reference scan-line passing through the center point of the element on a basis of the sub-virtual common point corresponding to a reference ultrasound image; set the second plurality of scan-lines based on the reference scan-line and the sub-virtual common point; and rotate the second center line to a third center line to set a third plurality of scan-lines.