Optical detection system for inner wall of cavity

The invention discloses an optical detection system for an inner wall of a cavity. The optical detection system on the inner wall of the cavity comprises a reflection module and a refraction module which are sequentially arranged from an object plane to an image plane; the reflecting module comprises a reflecting mirror; the refraction module comprises an objective lens group and an eyepiece group which are sequentially arranged from an object plane to one side of an image plane, and the objective lens group comprises a first lens with negative focal power and a second lens with positive focal power; the eyepiece group comprises a third lens with positive focal power and a fourth lens with negative focal power; the reflection module and the refraction module are coaxially arranged. Based on the reflection imaging technology of the reflection module and the refraction imaging technology of the refraction module, detection of the inner wall of the cavity is achieved, and the system is simple in structure and ha