The present disclosure provides an electronic display device including a backlight module, a light sensor, a storage device, an embedded controller, and a processing unit. The light sensor detects ambient light surrounding the electronic display device. The embedded controller controls intensity of the backlight module according to the ambient light and a brightness table of the storage device. The processing unit performs a basic input/output system to draw a brightness curve diagram according to the brightness table for users to adjust the curve of the brightness curve diagram during a boot process of the electronic display device and update the brightness table in the storage device according to the adjusted brightness curve diagram in response to a storing signal.