A display apparatus is provided, which includes a display module, a biosensor, an ambient-light sensor, and a display controller. The ambient-light sensor is configured to detect ambient-light brightness and an ambient-light color temperature of the display apparatus. The display controller is configured to receive a video signal from a host, and displays the video signal on the display module. When the biosensor detects that a user is located in front of the display apparatus, the biosensor transmits an image-adjustment control signal to the display controller to control the display apparatus to enter an image-adjustment mode. When the display apparatus is in the image-adjustment mode, the display controller adjusts screen brightness and a screen color temperature of the image signal displayed on the display module according to the ambient-light brightness and the ambient-light color temperature.