A face identification method, comprising: performing a distance detection to obtain a detected distance value which represents a distance between a distance detector and an object; determining whether the detected distance value is smaller than a distance threshold; when the detected distance value is smaller than the distance threshold, determining a luminance corresponding to the detected distance value and emitting an infrared light according to the luminance; capturing an infrared light image (Pir) and performing face identification to the infrared light image (Pir); and when the face identification is successful, performing a corresponding event; characterized in that wherein a range of the distance threshold is divided into a plurality of distance intervals (D1, D2, D3), the luminance has a plurality of set values (I1, I2, I3), and each of the plurality of distance intervals (D1, D2, D3) corresponds to one of the plurality of set values (I1, I2, I3); wherein emitting the infrared light according to the luminance comprising: controlling a driving circuit to switch a reference voltage (Vref) according to the detected distance value, so as to regulate a magnitude of a driving voltage (V-LED) output to an infrared light transmitter by a voltage regulator, so that the luminance of the infrared light transmitter corresponds to the detected distance value; wherein the driving circuit comprises two GPIO pins (GPIO-1, GPIO-2) respectively connecting to a base voltage in parallel through resistors, so that the reference voltage (Vref) is regulated according to a level state of the GPIO pins (GPIO-1, GPIO-2) and output to the voltage regulator through the GPIO pins (GPIO-1, GPIO-2). performing a distance detection to obtain a detected distance value which represents a distance between a distance detector and an object; determining whether the detected distance value is smaller than a distance threshold; when the detected distance value is smaller than the distance threshold, determining a luminance corresponding to the detected distance value and emitting an infrared light according to the luminance; capturing an infrared light image (Pir) and performing face identification to the infrared light image (Pir); and when the face identification is successful, performing a corresponding event; characterized in that wherein a range of the distance threshold is divided into a plurality of distance intervals (D1, D2, D3), the luminance has a plurality of set values (I1, I2, I3), and each of the plurality of distance intervals (D1, D2, D3) corresponds to one of the plurality of set values (I1, I2, I3); wherein emitting the infrared light according to the luminance comprising: controlling a driving circuit to switch a reference voltage (Vref) according to the detected distance value, so as to regulate a magnitude of a driving voltage (V-LED) output to an infrared light transmitter by a voltage regulator, so that the luminance of the infrared light transmitter corresponds to the detected distance value; wherein the driving circuit comprises two GPIO pins (GPIO-1, GPIO-2) respectively connecting to a base voltage in parallel through resistors, so that the reference voltage (Vref) is regulated according to a level state of the GPIO pins (GPIO-1, GPIO-2) and output to the voltage regulator through the GPIO pins (GPIO-1, GPIO-2). controlling a driving circuit to switch a reference voltage (Vref) according to the detected distance value, so as to regulate a magnitude of a driving voltage (V-LED) output to an infrared light transmitter by a voltage regulator, so that the luminance of the infrared light transmitter corresponds to the detected distance value; wherein the driving circuit comprises two GPIO pins (GPIO-1, GPIO-2) respectively connecting to a base voltage in parallel through resistors, so that the reference voltage (Vref) is regulated according to a level state of the GPIO pins (GPIO-1, GPIO-2) and output to the voltage regulator through the GPIO pins (GPIO-1, GPIO-2).