Provided is a three-dimensional (3D) ultrasound system and a 3D ultrasound system operating method that may obtain 3D ultrasound data with respect to an object inside a human body to determine an accurate sagittal view. The 3D ultrasound system may include a scanner to generate ultrasound data including image data generated by scanning an object inside a human body, a processing unit to detect a center point of the object from the generated ultrasound data, and to generate, on the ultrasound data, a virtual plane on which the detected center point is placed, and a controller to rotate the ultrasound data based on the image data included in the virtual plane and to determine a sagittal view with respect to the object.