The present disclosure relates to a method and a device for determining ambient brightness and a storage medium. The method includes: outputting a control signal by the IC to the display screen, the control signal being configured to control brightness of the display screen; sending an instruction message by the IC to the brightness sensor when a level of the control signal is a first level, the first level being configured to control the display screen to display black, the instruction message being configured to instruct the brightness sensor to acquire an optical signal passing through the display screen; and determining an ambient brightness value by the brightness sensor based on the optical signal.