A backlight control method for a surface light-emitting device is provided. The backlight control method includes generating a plurality of driving currents to drive the surface light-emitting device such that a plurality of backlight zones generate a plurality of brightness values, measuring the plurality of brightness values of the plurality of backlight zones, calculating a plurality of uniformities of the plurality of backlight zones according to the plurality of brightness values and setting a plurality of target uniformities, generating a plurality of adjustment values according to the plurality of uniformities, the plurality of target uniformities and a plurality of adjustment coefficients corresponding to the plurality of backlight zones, and generating a plurality of adjusted driving currents to drive the plurality of backlight zones according to the plurality of adjustment values and the plurality of driving currents.