Abstract: The present disclosure provides a mounting structure for an endoscope front-end piece, including a front-end piece, a pull rod, and an adjustment mechanism. The front-end piece includes a front end clamped onto a port of an endoscope tube, and a rear end extended into the endoscope tube; a sealant groove is formed in a portion of the front-end piece contacting an inner wall of the endoscope tube; the pull rod includes a front end connected to the front-end piece, and a rear end extended into an endoscope tube socket; and the adjustment mechanism is located in the endoscope tube socket, and is capable of both compressing the endoscope tube socket and tensioning the pull rod through threaded transmission, thereby allowing the front-end piece to retain on the port of the endoscope tube, and adjusting a mounting gap and a mounting pressure. The structure realizes gapless mounting of the front-end piece.