1. A 3D image display method, comprising: receiving a broadcast signal including video data and 3D object data; decoding the 3D object data, wherein the 3D object data includes text or image information about a 3D object, output location information of the 3D object, and disparity information of the 3D object; acquiring a parallax value from the disparity information and calculating a distortion compensation factor using the parallax value, wherein the distortion compensation factor is calculated by the distortion compensation factor=(an interocular distance value−the parallax value)/an interocular distance value; adjusting a display size of the 3D object by multiplying the display size of the 3D object by the calculated distortion compensation factor; and displaying the 3D object having the adjusted display size.