The invention discloses a multifunctional smart watch based on cloud service, which comprises a watch body, a first watch band and a second watch band, wherein the watch body comprises a shell; a touch display screen is embedded on the upper surface of the shell; the bottom surface of the shell, close to the finger pointing side wall position in the case of wearing, is provided with a USB plug fixing groove; a USB plug is rotarily connected in the USB plug fixing groove; and a cloud processor is fixed in the shell. The USB plug which can be hidden and stretched to the outside is rotarily connected in the USB plug fixing groove on the back surface of the shell of the watch body, and due to the structure, charging can be carried out directly through the USB plug, and the trouble of a user bringing a charging wire can be omitted; and a cover plate bonded and fixed with a mirror surface through glue is rotarily connected onto the back surface of the shell of the watch body through a hinge,mirror use by the user is facilitated, and functions of the smart watch are enhanced.