This research attempts to analyze the performativity of theatrical languages in post-drama by the philosopher Wittgenstein's theory of “Language game”. Since Hans Thies Lehmanna established the concept of post-drama in 1999, discussions have been active on the performativity. Based on Wittgenstein's book 『Philosophical Investigations』, this thesis seeks to study how post-drama is creating a new language game with audiences. Furthermore, it will study how the post-drama language, which focuses on performativity, has a common meaning among its members. Theatrical languages of post-drama are not limited to dictionary meanings, but rather expand the language's expression in its own way. The audiences understand the meaning of the actors' actions through their senses and it creates a “public language” by bringing out rules among the members who exist together in the space. In conclusion, post-drama does not rule out the use of language, but produces results that emphasize the “Performativity of language” by expanding its meaning more actively. Through this process, the language standardization and violence of traditional narrative structures are disbanded, and the original meaning is expanded to guide changes in the audience's lives.