The invention discloses an endoscope tie gun and an application method thereof, which can be applied in the medical field. A medical lashing band is utilized to bind disease carrier tissues. The gun body of the tie gun comprises a gun handle, a gun head and a long gun barrel which can penetrate into a disease carrier, wherein a similar T-shaped trigger structure is arranged in front of the gun handle of the gun body and is provided with a transverse transmission chute which can be matched with a raised line arranged on the long gun barrel of the gun body to realize transverse reciprocating dragging between the trigger structure and the gun body. The invention has the beneficial effect that the direct dragging transverse transmission is adopted between the gun handle of the endoscope tie gun and the trigger; the invention has the characteristics of reasonable design, simple structure, convenient operation, favorable binding effect and the like; a cutter can cut off a ribbon according to the practical used length, has reliable ligation effect and especially has better fastening and ligation effect on thicker ligation objects. Because of directly aiming at minimal invasion or endoscope operations, the invention has direct and obvious effect, solves the problem that binding grows out of nothing, saves operation time, further perfects minimal invasion idea and provides further guarantee for operation safety.