The invention provides a lighting circuit. The lighting circuit comprises a driving circuit, a power supply circuit, a distance measurement circuit and a light source, wherein the driving circuit is connected with the light source; the driving circuit is used for controlling the current output to the light source; the power supply circuit is connected with the driving circuit; the power supply circuit is used for supplying power to the driving circuit and the distance measurement circuit; the distance measurement circuit is connected with the driving circuit; and the distance measurement circuit is used for detecting at least one kind of the distance between a target object and the lighting circuit, the height of the target object, and the area of the target object. By adoption of the lighting circuit, the functions of dimming, distance measurement, detection of the height and the area of the target object, and the like can be realized, so that the user experience can be improved.