The invention discloses a fixator. The fixator comprises a mounting base as well as a locking assembly and a buckling assembly which are arranged on the mounting base, wherein the locking cylinder comprises a sleeve, a lock tongue which is sleeved by the sleeve, a connecting rod which is connected with the tail end of the lock tongue, an elastic part which sleeves the connecting rod, a cover plate which is detachably connected to the upper end of the sleeve, a bump which is arranged on the upper surface of the cover plate, and a handle which is arranged at the tail end of the connecting rod; the buckling assembly comprises a supporting base, a guide rail arranged on the supporting base, a slide block arranged on the guide rail, baffle plates which are arranged at the two ends of the guide rail, a spring which is connected between the slide block and the baffle plate at one side, and a lock body which is arranged on the slide block for fixing a buckle body. According to the fixator disclosed by the invention, the front section of the handle body is rotatably connected with the tail end of the connecting rod and the bump; when the handle is rotated, the handle body rotates around the bump and drives the connecting rod to perform lifting motion; when the handle is loosened, the lock tongue extends out of the sleeve under action of elastic force of the elastic part for fixing; and when the handle is downwards pressed, the lock tongue is driven by the connecting rod to upwards slide into the sleeve, so that the functional needs of fixing and loosening the fixator are effectively realized.