The present disclosure provides a head-mounted display device including a first OLED display, a first temperature sensor, and a controller. The first OLED display is configured to display image data. The first temperature sensor is disposed within the head-mounted display device and is configured to sense the first device temperature of the first OLED display. The controller is electrically connected to the first OLED display and the first temperature sensor. The controller outputs the image data and a first display driving voltage to the first OLED display. The controller adjusts the first display driving voltage to control the brightness performance of the first OLED display according to the change of the first device temperature.