The plot structure of Oedipus Rex follows the classic Greek tragedy format, which consists of five main parts:

1. Prologue: The play opens with a prologue, which sets the scene and introduces the main characters. In Oedipus Rex, the prologue establishes the background of the story and introduces the protagonist, Oedipus, as the king of Thebes.
2. Parodos: The chorus enters and sings a song that provides further background information and sets the tone for the play.
3. Episodes: The episodes are the main action of the play, where the plot unfolds and the characters interact. In Oedipus Rex, the episodes involve Oedipus' investigation into the murder of the previous king, Laius, and his discovery of his own guilt in the crime.
4. Stasima: The stasima are choral odes that follow each episode and provide commentary on the action. In Oedipus Rex, the stasima reflect on the themes of fate, free will, and the consequences of human actions.
5. Exodos: The exodos is the final scene of the play, where the characters exit and the chorus sings a concluding song. In Oedipus Rex, the exodos sees Oedipus blinded and exiled from Thebes, while the chorus reflects on the tragic nature of his downfall.