The invention discloses a gunlock speed reduction mechanism of a pistol, and belongs to the technical field of pistols. The gunlock speed reduction mechanism comprises a gunlock, a gun barrel and a binding base. The gun barrel is rotationally installed on the binding base. A spiral groove is formed in the gunlock. A protrusion corresponding to the spiral groove is arranged on the gun barrel. When the gunlock recoils, the protrusion collides with the spiral groove, part of energy of gunlock recoiling is offset, and the aim of gunlock speed reduction is achieved. When the pistol using the gunlock speed reduction mechanism fires a bullet, the gunlock recoils in place at a low speed, the phenomenon that an existing pistol is prone to causing obvious hand shaking is eliminated, and the shooting comfort degree is improved. In addition, the gunlock speed reduction mechanism further has the beneficial effects of being simple in structure, good in reliability, wide in application range and the like.