The study of images is the path leading to an understanding of the value system of medieval man. If in the study of Christian ideas about the Mongols, historical and literary works were given some attention, then iconographic documents were often used only as illustrations to the text and were considered as something secondary. One of the poorly studied topics is the study of «imaginary heraldry», which was given to the Mongols by French miniaturists of the XIV-XV centuries. The research is based on the approach of the American art critic, M. A. Camillus, which involves the study not of what was «really», but of what was brought into the situation described by medieval scribes. The model of our analysis of the content of miniatures is based on the methodology of the German researcher Erwin Panofsky, according to which the analysis of miniatures takes place in three stages: 1) pre-iconographic description; 2) iconographic analysis; 3) iconological interpretation. Our research is based on French manuscripts containing images of the Mongols with various heraldic symbols, written evidence, numismatic and cartographic sources. During the work, it was noted that the Mongolian heraldry is presented in the format of shields and banners. Each element has its own color – red, orange, blue, yellow. The following heraldic signs were identified: a dragon, a six-pointed star, a crescent, a two-pronged tamga, a «king's head», lilies, a «star of David», various geometric shapes of figures, etc. It was also determined that the image of heraldic symbols on the miniatures carries a certain symbolism – social and ethnic. With the help of «imaginary heraldry», Christian miniaturists defined the place of the Mongols in the social stratigraphy or emphasized ethnicity.