An electronic device includes a light sensor and a microcontroller connected to the light sensor, where the light sensor is configured to acquire an ambient luminance signal of a current time point; and the microcontroller is configured to: read the ambient luminance signal of the current time point from the light sensor, and obtain through calculation a first target backlight brightness value of the electronic device at the current time point according to the ambient luminance signal of the current time point, where the microcontroller is further configured to: if the electronic device is in a normal screen-on state, adjust from a first initial backlight brightness value to the first target backlight brightness value step by step, where the first initial backlight brightness value is a first target backlight brightness value of the electronic device at a previous time point.