This research aims to explore the role and significance of the betel nut symbol in Taiwan's history based on Saussure's semiotic theory. Betel nut is divided into betel nut tree, betel nut leaf, betel nut, betel nut flower and betel nut heart, a total of five parts. The functions of betel nut are divided into three types: daily life, marriage contract ceremony and sacrificial ceremony. Ethnic minorities, that is, different ethnic group have different signs in different periods. The associative relations or arbitrary relationship between signifier and signified is also discussed. In the future, how to expand the various signs of betel nut and use it in cultural and creative products can be further discussion.