Optical stereo microscope is a kind of binocular microscope with stereoscopic sense of positive image. It can observe objects from different angles and make binocular microscope cause stereoscopic sensation. The observation body does not need to be processed and made. It can be observed directly under the lens with lighting. It looks upright and easy to operate and dissect. It is a kind of stereoscopic microscope with positive image, which is widely used in material macroscopic surface observation, failure analysis, fracture analysis and other industrial fields. It is a kind of stereoscopic visual instrument, which is widely used in biology, medicine, agriculture and forestry, industry and marine biology.