A fast releasable dog leash and muzzle device comprises a main leash, a detachable band, a secondary leash, and a muzzle. The main leash is provided with a pull strip at a suitable location at an upper end, and a ring and an elastic band at a tailing end. The pull strip is connected to a steel cable that projects a suitable length from the tailing end of the main leash. The detachable band is formed with an eyelet at an upper end and a clip at a lower end. The leash passes through the elastic band at the tailing end of the main leash through the detachable band； the ring of the main leash passes through the eyelet of the detachable band； the steel cable of the main leash is penetratingly disposed in the ring, so that a pulling effect of the ring of the main leash locking and fixing the steel cable makes the detachable band coupled to the main leash to form a complete leash, and an effect of traction can be achieved by having the clip of the detachable band hook on a collar of a dog. The muzzle comprises a muzzle body and a neck band. The muzzle body is provided with a combination band, a combination loop, and a female insertion clip. The neck band is provided at one end with a combination terminal and a fixing strip. The fixing strip has a front end that is provided with a pull ring. Another end of the neck band is connected to a male insertion clip and is available for adjustment of the length of the neck band.An assembly method of the muzzle is that the muzzle body is rolled up from an inner surface to form a conic shape, and the combination terminal of the neck band is inserted into the combination band and the combination loop and is covered and fixed by the fixing strip of the neck band to form a muzzle device. When the muzzle is fit to the snout of a dog, the neck band is adjusted to a suitable length and is looped around the neck of the dog with the male insertion clip on the neck and the female insertion clip mutually engaging each other to complete wearing
