The design method of flexible infrared optical imaging system based on optical fiber transmission is discussed. The split layout of optical imaging front module, optical fiber image beam and optical imaging rear module is used to achieve efficient matching of optical aperture and refrigeration detector through reasonable optimization design. The design method effectively reduces the optical load quality of the servo rotating structure, compresses the shape and size of the optical load, and effectively expands the new way of flexible layout of the optical machine system. Through the design method, with the servo rotation structure, arbitrary direction imaging in the hemispheric airspace can be realized.