The company offers inspection on high-temperature furnaces via the high temperature furnace periscope which can be stretched into the furnace to keep inspecting furnace damages according to the actual demand for 24 hours a day (similar to gastroscopy). With the use of the optical imaging system, a high resolution camera takes pictures or videos, and the periscope can snap a clear image and conduct remote observation. It can adjust the optical focal length according to the observation distance and adjust the aperture depending on light brightness. Through taking photos and video, and storing them on the computer or printing them out, the company can carry out comparison and analysis of the furnace at different time section, make an accurate evaluation of the working state of the furnace, make a timely and accurate maintenance schedule, conduct maintenance process supervision and check the maintenance effect.