Abstract: Smart glasses which is automatically activated by being used includes a display screen, a frame and two legs. A switch is located on a joint between the frame and one of the two legs. The switch turns on when the two legs rotate away and the switch turns off when the two legs rotate together. A state of the switch is acquired when the smart glasses is in a sleep mode and the display screen is activated when the switch turns on, and sensors on the smart glasses can further sense and detect physical characteristics of a user to identify the user and his authority and thus prevent or allow the automatic activation.