Various embodiments of ultrasound system and method of selecting a 2D slice image from a 3D ultrasound image are provided. One embodiment of the ultrasound system comprises: a 3D ultrasound image acquisition unit configured to acquire a 3D ultrasound image of a target object; a 2D slice image selection unit including a control volume unit, the 2D slice image selection unit being configured to be rotated and/or moved by an operator; and a processor coupled to the 3D ultrasound image acquisition unit and the 2D slice image selection unit. At least one selection plane is formed by the control volume unit as a reference plane to select at least one 2D slice image from the 3D ultrasound image. The processor is configured to extract at least one 2D slice image corresponding to the at least one selection plane from the 3D ultrasound image. The 3D ultrasound image or the at least one selection plane are rotated and/or moved together with the control volume unit.