Self-adaptive endoscope working distance adjustment system and endoscopic imaging system

A self-adaptive endoscope working distance adjustment system, comprising:

• an image relay sheath, a lens holder disposed on an image side of the image relay sheath, a protective sheath sleeved on an outer side of the image relay sheath, and a working distance auxiliary adjustment system disposed between the protective sheath and the lens holder and/or between the protective sheath and the image relay sheath, wherein
• the lens holder axially protrudes to form a support portion, and an imaging lens is disposed inside the image relay sheath away from the image side;
• the protective sheath comprises:
• an outer sheath tube axially extending over the imaging lens, a sheath tube connection portion partially sleeved on an outer side of the support portion and connected to the outer sheath tube, and a protective lens disposed at an object-side end inside the outer sheath tube;
• and
• the working distance auxiliary adjustment system is configured to adjust a relative axial position between the imaging lens and the protective lens and to maintain a working distance between the protective lens and the imaging lens.