A display apparatus and an image display method of the display apparatus are provided, and the image display method includes following steps. Video contents that include a plurality of single frame images are received. A detection zone of the single frame images is determined according to a current scale mode of the display apparatus, and the different scale modes correspond to the different detection zones. The detection zone of each single frame image is detected to determine an image format of the video contents. A play mode of the display apparatus is adjusted according to the image format, and the video contents which are scaled are displayed by the display apparatus in the play mode.