The structuralism approach is a valuable legacy of the French anthologist Levi Strauss. He considered social phenomena and mythological narratives as text and analyzed the story or phenomenon by extracting binary oppositions and drawing a table of mythemes. In the present study, the exogamy of Zal, Bijan and KeyKavus in Shahnameh were investigated in a descriptive-analytical way and based on Strauss theory. The results showed that the quadruple permutations of each of these marriages correspond to the mathematical model proposed by Strauss and their narrations also have many binary oppositions that the most important of them (us/them) expresses the importance of intergroup demarcations with out-group people for Iranians. Marriage with foreigners is not desirable due to mixing with such nationality; but because in this marriages, a part of foreign land is taken over by Iranians, it reduces the ugliness of exogamy. In these marriages, the weakening of family ties in the form of father/son or father/daughter opposition is high.

Finally, it was found that the structure of exogamy in Shahnameh matches the mathematical model proposed by Le'vi Strauss and the four and Final permutations of these marriages are: 1. a foreign factor takes the hero away from hero’s land; 2. the hero marriages a girl from a foreign land; 3. the hero stay in foreign land; 4. the hero/ hero’s successor return ti Iran.