A disposable protecting cover for an endoscope, the endoscope comprising a endoscope and a disposable valve disk, and the disposable protecting cover comprising a disposable sheath, a clamping tube, a disposable suction tube, a three-way sealing cap, a water air tube, and a protecting cover comprising a hand entrance and an instrument insertion opening. A support ring is disposed in the front of the disposable sheath, a convex portion and a concave portion are respectively disposed on both sides of the support ring and fit with a concave portion and a convex portion on a head of the endoscope, the water air tube is connected to the disposable sheath, a one-way valve is disposed on the water air tube and outside the disposable sheath, the protecting cover is in the shape of a cap and made of transparent film, the protecting cover operates to cover an operating portion of the endoscope of the endoscope, the instrument insertion portion is elastically fit with an upper opening of the three-way sealing cap, a suck-in connector and a suck-out connector are disposed on a valve seat of the disposable valve disk, and connected to the disposable suction tube, and the suck-in connector, the suck-out connector, and the disposable suction tube are dispose outside the endoscope.
