A display apparatus outputs a video frame according to ambient brightness. The display apparatus includes an ambient sensor for sensing the ambient brightness of the display apparatus to generate an ambient brightness sensing signal; and a control circuit, coupled to the ambient sensor, for dynamically adjusting display characteristics of the video frame according to the ambient brightness sensing signal without adjusting a light source of the display apparatus. γ (gamma) curve characteristics of the display apparatus can be adjusted to change the display characteristics (brightness and color temperature) of the outputted video frame without causing any damage on the light source hardware (such as the cold cathode fluorescent lamp (CCFL)).