NIRS (Seafloor Nodule Image Recognition System) is a processing system of sea floor poly-metallic nodules images. Those images, with a character of the point light source (light in the center and dim on margins in the photo), can be corrected to such an extent that they have a character of parallel light according to the inverse ratio relation between the light intensity and the power of the light distance. According to the pattern recognition theory. the nodule image and its background can be segregated by some features such as grey and shape; then the edge of each nodule can be circled, the coverage and the estimated abundance can be calculated, and all the information can be stored in the database. A film scanner with resolution 1850DPI is configurated and a high clarity image can be displayed. The processing results of the seafloor nodule photo in cruises DY85-1 and DY85-3 have been analysed and five types of the nodule photos can be distinguished. The best operation method of this system has been put forward and the evalution method of quality of photo processing has been discussed.