The invention relates to a device of anti-fogging endoscope system and its method, falling in the minimally invasive medical technical field, wherein a near-infrared lighting source for anti-fogging is added on the basis of the traditional endoscope system, a beam of which is coupled into the lighting transmission path in color combination, and changes material properties of a distal optical window plate to transmit the visible light, ensuring that surgical filed is lighted by white light, while the temperature of the distal optical window plate is elevated by absorbing energy of the near-infrared light to reduce the temperature difference between the distal optical window plate of endoscope and a human body, to realize the purpose of anti-fogging. Comparing the invention with anti-fogging ways of preheating with physiological saline, smearing anti-fogging oil, and so on, as to the doctor's performances, the invention has the more convenient and easier advantages, and there is not a latent risk of incompletely disinfecting when using physiological saline, anti-fogging oil and so on, which is suitable to be used in various endoscopic operations, and is specially suitable to be used in the endoscopic operations wherein the endoscope needs to be repeatedly inserted into the human body and drawn out from the human body, in order to play the effect of anti-fogging.
