A backlight driving circuit includes a light driving unit, which includes a constant current unit, and a light source operated by the constant current unit. The light driving unit further includes a feedback control unit and a detection circuit. The detection circuit detects the light source and outputs at least a voltage feedback signal to the feedback control unit. The feedback control unit obtains a prestored power parameter corresponding to the voltage feedback signal and outputs an adjusting signal to the constant current unit to adjust the constant current of the light source.