From the diachronic perspective of art history, contemporary art has dominated the development of art and is conceptual. From the synchronic perspective of art criticism, the study of contemporary art involves conceptuality and visuality, which is the study of the generation and interpretation of meaning. At this intersecting node, semiotics appears. Interpreting art from the perspective of semiotics is an academic phenomenon in the 20th century. While in the 21st century, semiotics advanced greatly, and through it, we have gained from investigating contemporary art. From the development and current situation of semiotics, this lecture reveals the validity of semiotics' formal analysis to the conceptuality and visuality of contemporary art, thus explaining the value and significance of semiotics.