Cephalopod beaks are important tissues for the study of cephalopod organisms. In order to achieve the accurate measurement of pigmentation of cephalopod beaks and to investigate the role of pigmentation in the discriminative classification of cephalopod beaks, this study selected the beaks of three cephalopods, the Middle East Pacific Dosidicus gigas, the northwest Pacific Ommastrephes bartrami and the Middle East Atlantic Ommastrephes pteropus.The pigmentation is visualised on the basis of its lateral view image according to four classes: class Ⅰ(black), class Ⅱ(grey), class Ⅲ(light grey) and class Ⅳ(transparent). The ratio of the area of pigmentation to the area of the hood-wing region and the area of the crest-lateral wall region was calculated for the four classes of Dosidicus gigas, Ommastrephes bartrami and Ommastrephes pteropus, respectively.The difference in pigmentation between the three cephalopods was analysed using stepwise discriminant analysis, and the correct rate of discrimination was 74.4%.It is suggested that there are some differences in the pigmentation of the beak of the three cephalopods, and that these differences may be due to the different life characteristics and feeding habits of the three cephalopods.The study achieves numerical and precise classification of pigmentation classes in cephalopod beak, which is a new quantitative measurement method and provides new ideas for the study of pigmentation in cephalopod beak.