The invention discloses a wearable device and a wrist band quick disengagement method thereof. The wearable device comprises a dial plate, a wrist band, at least one connecting shaft and at least one driving device, wherein the dial plate is internally provided with a control master board. At least one connecting shaft is connected between the dial plate and the wrist band. At least one driving device is arranged in the dial plate and is electrically connected with the control master board and is connected with at least one connecting shaft. The control master board is used for supplying electric energy to at least one driving device when a high-temperature signal is received so that at least one driving device drives at least connecting shaft move for disengaging with the wrist band, thereby realizing disengagement between the wrist band and the dial plate. According to the wearable device and the wrist band quick disengagement method thereof, when dial plate temperature increase occurs, the connecting shaft can be moved for disengaging from the wrist band through making the master board quickly supply electric energy to the driving device, thereby ensuring quick separation between the wrist band and the dial plate, preventing high-temperature scald of a user and ensuring high safety in use by the user.