Peanuts are especially susceptible to contamination of aspergillusflavus and aspergillusparasiticus, which can produce a kind of highly toxic substance, aflatoxin.The study about the separation technology of aflatoxin-infected peanuts before processing can effectively isolate the source of contamination by taking precautions instead of executing treatment on the contamination, thus being of great significance on guaranteeing food safety.For the purpose of effectively eliminating the red-skin peanuts with excessive aflatoxin levels from raw materials, one technology concept of one-by-one sorting method using the exclusive fluorescent signal of the red-skin peanuts with excessive aflatoxin levels was conceived here referring to the existing color sorting system.In this study, the fluorescence spectra of 100 red-skin peanut samples with representative appearance were determined using Cary Eclipse fluorescent spectrophotometer (at an excitation wavelength of 365 nm, an emission wavelength in the range of 400~600 nm and discharge voltage of 400 V).According to the fluorescence intensity distribution of samples at the wavelength of 450 nm, all these 100 red-skin peanut samples were divided into 8 groups.The aflatoxin content for each group of samples was determined using the standard method, GB/T 18972-2003 Determination aflatoxin content in food-Cleanup by immunoaffinity chromatography determination by high-performance liquid chromatography and fluorimeter.By comparing the surface fluorescence spectroscopy of the 8 groups with the obtained results from the standard method, the fluorescence spectroscopy characteristics of the the red-skin peanuts with excessive aflatoxin levels were primarily determined.The accuracy rate of discriminating the aflatoxin levels of red-skin peanuts using surface fluorescence was evaluated by means of drawing the box-plots of the fluorescence intensity ratio at 450 nm/490 nm and 460 nm/490 nm.Taking the colony laser fluorescence microscope as a platform, and using a laser beam expander that can enlarge the projection area of the excitation light to cover 2-3 peanuts, the fluorescence images of the red-skin peanuts with excessive aflatoxin levels were taken using a monochrome fluorescence image acquisition system, which was set up by putting a band-pass filter (460±5 nm) at the front of an industrial camera objective.The results of this study showed that there was a correlation between the determination of the aflatoxinlevels in red-skin peanuts by using fluorescent spectrophotometer at an excitation wavelength of 365 nm to detect the fluorescence intensity at 450 nm and the aflatoxin measurement using the standard method, which means that while the fluorescence intensity at 450 nm is greater than 30 a.u., the aflatoxincontent exceeded the national standard limit.Thus, the characteristic fluorescent signal of the excessive aflatoxin contamination can be intended as follows: the emission spectra generate fluorescence peaks at 420~460 nm and the fluorescence intensity at 450 nm was greater than 30a.u., while under an excitation wavelength of 365nm.According to the calculation based on the Whisker upper and lower limit, the overlapping ratio of the fluorescence intensity was at 450 nm and 490 nm is 19%, indicating that the discrimination accuracy rate of red-skin peanuts with excessive aflatoxin levels was 81%.Meanwhile, using the fluorescence image acquisition system, the monochrome images of the aflatoxin excessive peanuts were obtained, which displayed blue light spot for the contaminated peanuts once the surface fluorescence intensity was greater than 40a.u.Overall, the study indicates that the surface fluorescence signal can be the exclusive light signal of the red-skin peanuts for on-line, nondestructive and one-by-one sorting, for the purpose of eliminating the red-skin peanuts with excessive aflatoxin levels.