A light-emitting device driving circuit and a method thereof are provided. A terminal of a light-emitting device is coupled to a supply voltage and a cathode of a diode via an inductor, and the other terminal is coupled to an anode of the diode. The light-emitting device driving circuit includes a switch, a current-sensing circuit, and a switch control circuit. The current-sensing circuit is coupled to the anode of the diode via the switch to determine whether or not to generate a turning-off control signal according to a conducting-current value of the switch. The switch control circuit controls an on/off state of the switch, and turns off the switch according to the turning-off control signal. Besides, the switch control circuit compares the conducting-current value with a reference-current value to generate a comparing result to dynamically adjust a time length of turning off the switch accordingly.