A lighting device, comprising: a light body, and a battery pack; wherein the light body comprises a light-emitting unit and a first universal serial bus, USB, interface electrically coupled to the light-emitting unit; the battery pack comprises a power supply and a second universal serial bus interface electrically coupled to the power supply; the first USB interface comprises a first data transmission terminal and a first power terminal; the first data transmission terminal is configured for establishing data communication with the second USB interface, and the first power terminal is configured for supplying power to the light-emitting unit; the second USB interface comprises a second data transmission terminal and a second power terminal; the second data transmission terminal is configured for establishing data communication with the first USB interface, and the second power terminal is configured for supplying power to the first power terminal; and the first data transmission terminal is grounded, and the second data transmission terminal is coupled to a switch circuit which is configured to switch on power transmission from the power supply to the second power terminal when the second data transmission terminal is at a low level; and wherein the first data transmission terminal comprises a first data positive pin and a first data negative pin; the first data positive pin and the first data negative pin are grounded; the second data transmission terminal comprises a second data positive pin and a second data negative pin; the second data positive pin and the second data negative pin are coupled to the switch circuit; the power supply is capable of supplying electric power to the second power terminal through the switch circuit; and wherein the switch circuit comprises a first metal oxide semiconductor transistor; the second data positive pin is coupled to a first MOS transistor gate region; the power supply is coupled to a first MOS transistor drain region; and a first MOS transistor source region is coupled to the second power terminal. a light body, and a battery pack; wherein the light body comprises a light-emitting unit and a first universal serial bus, USB, interface electrically coupled to the light-emitting unit; the battery pack comprises a power supply and a second universal serial bus interface electrically coupled to the power supply; the first USB interface comprises a first data transmission terminal and a first power terminal; the first data transmission terminal is configured for establishing data communication with the second USB interface, and the first power terminal is configured for supplying power to the light-emitting unit; the second USB interface comprises a second data transmission terminal and a second power terminal; the second data transmission terminal is configured for establishing data communication with the first USB interface, and the second power terminal is configured for supplying power to the first power terminal; and the first data transmission terminal is grounded, and the second data transmission terminal is coupled to a switch circuit which is configured to switch on power transmission from the power supply to the second power terminal when the second data transmission terminal is at a low level; and wherein the first data transmission terminal comprises a first data positive pin and a first data negative pin; the first data positive pin and the first data negative pin are grounded; the second data transmission terminal comprises a second data positive pin and a second data negative pin; the second data positive pin and the second data negative pin are coupled to the switch circuit; the power supply is capable of supplying electric power to the second power terminal through the switch circuit; and wherein the switch circuit comprises a first metal oxide semiconductor transistor; the second data positive pin is coupled to a first MOS transistor gate region; the power supply is coupled to a first MOS transistor drain region; and a first MOS transistor source region is coupled to the second power terminal.