An electronic device comprising: a housing; a display (160, 320) viewable via a front surface of the housing and configured to display a screen; a camera including a camera sensor (180, 330) disposed in at least a portion of the front surface of the housing and configured to acquire information related to external illuminance from an image acquired by the camera sensor; an illuminance sensor disposed under the display (160, 320) and configured to measure the external illuminance; a processor operationally connected to the display (160, 320), the camera, and the illuminance sensor; and a memory operationally connected to the processor, wherein the memory is configured to store instructions that, when executed, cause the processor to control the electronic device to: detect a turn-on event of the display (160, 320), turn on the illuminance sensor when the display (160, 320) is turned on, obtain the external illuminance through the illuminance sensor for a specified period, determine whether the external illuminance is less than a specified first illuminance value, turn-on the camera sensor (180, 330) based on the external illuminance being less than said specified first illuminance value, acquire an exposure time and a brightness value from preview image information acquired by the camera sensor (180, 330) in an acquisition interval, compensate the external illuminance using the acquired exposure time and/or the brightness value when the external illuminance is less than said specified first illuminance value, and control a luminance of the display (160, 320) according to the compensated external illuminance. a housing; a display (160, 320) viewable via a front surface of the housing and configured to display a screen; a camera including a camera sensor (180, 330) disposed in at least a portion of the front surface of the housing and configured to acquire information related to external illuminance from an image acquired by the camera sensor; an illuminance sensor disposed under the display (160, 320) and configured to measure the external illuminance; a processor operationally connected to the display (160, 320), the camera, and the illuminance sensor; and a memory operationally connected to the processor, wherein the memory is configured to store instructions that, when executed, cause the processor to control the electronic device to: detect a turn-on event of the display (160, 320), turn on the illuminance sensor when the display (160, 320) is turned on, obtain the external illuminance through the illuminance sensor for a specified period, determine whether the external illuminance is less than a specified first illuminance value, turn-on the camera sensor (180, 330) based on the external illuminance being less than said specified first illuminance value, acquire an exposure time and a brightness value from preview image information acquired by the camera sensor (180, 330) in an acquisition interval, compensate the external illuminance using the acquired exposure time and/or the brightness value when the external illuminance is less than said specified first illuminance value, and control a luminance of the display (160, 320) according to the compensated external illuminance. detect a turn-on event of the display (160, 320), turn on the illuminance sensor when the display (160, 320) is turned on, obtain the external illuminance through the illuminance sensor for a specified period, determine whether the external illuminance is less than a specified first illuminance value, turn-on the camera sensor (180, 330) based on the external illuminance being less than said specified first illuminance value, acquire an exposure time and a brightness value from preview image information acquired by the camera sensor (180, 330) in an acquisition interval, compensate the external illuminance using the acquired exposure time and/or the brightness value when the external illuminance is less than said specified first illuminance value, and control a luminance of the display (160, 320) according to the compensated external illuminance.