A smart bracelet includes an endless belt, the endless belt including a mounting cavity and elastic bands provided at both ends of the mounting cavity, and a cross section of the elastic band is a fan ring having a central angle greater than one hundred and eighty degrees, the endless band A connecting ear is formed at the lower end of the issue, and a silicon buckle is connected to the connecting ear through a snap button. A control box is provided in the mounting cavity, a placement hole is provided at the rear end of the installation cavity, and a front end of the installation cavity is provided with A positioning hole, a mounting hole is provided at the front end of the mounting cavity, a sleeve is provided at the upper end of the elastic band, and a spray device is provided in the sleeve, the control box includes a box body, and left and right ends of the box body are provided with The positioning shaft matches the positioning hole, and the upper end of the box body is provided with a touch screen, the front end of the box body is provided with an adjustment button, and the inside of the box body is provided with an instrument room, the instrument room is provided with a single-chip microcomputer, and the instrument room is provided with There are a lithium battery, a temperature detection sensor, a Bluetooth module, a light sensor and an accelerometer which are electrically connected to the single chip microcomputer, the single chip microcomputer is electrically connected to the touch screen and the adjustment button, and the front end of the installation cavity A backup energy storage device is provided. The backup energy storage device includes a casing, and a rear end of the casing is provided with an insertion rod matching the mounting hole. The interior of the casing is provided with a backup lithium battery. The end is provided with a USB connector electrically connected to the single chip microcomputer.