What makes Stanley an anti-hero in the play?

Stanley is not in this story. Do you possibly mean "A Streetcar Named Desire?"

i really mean"The Birthday Party", Stanley is very afraid by the coming of the two gentlemen. they takes him and he shows no reactions. i think that what make him an anti-heéro.

Sorry - I thought you meant the short story of the same title.

An anti-hero acts against what would be considered heroic qualities. His attempted rape of Lulu, his fear of the two gentlemen (suggesting that he perhaps has something to hide), and his qualities which show him not to be a good guy are perhaps anti-hero characteristics.

ok thank you very much.