The invention relates to a separation sleeve for oral cavity, belonging to the technical field of medical appliance. The separation sleeve is composed of an inner separation surface, an outer separation surface, an inner attached ring and an outer attached ring; wherein, the inner separation surface is a film-shaped structure and the edge of the inner separation surface is fixedly connected with the inner attached ring; the outer separation surface is a film-shaped structure provided with a film-free area, the edge of the inner side film of the outer separation surface is fixed with the outerattached ring; the inner attached ring and the outer attached ring are folded and unfolded along the horizontal line which serves as the axis and is where the center of the ring is located; the folding and turning parts of the inner attached ring and the outer attached ring are fixedly connected by an attached ring joint; gap is arranged between the inner attached ring and the outer attached ring.The device of the invention can ensure a more secure, convenient and fast, comfortable and humanized oral surgery.