The title is one of situational irony as it develops in the story. The term "lottery" suggests an opportunity to win something of value, a nice prize or perhaps a large amount of money. The odds of winning a lottery are very small because many people usually participate, but for the lucky winner, the pay-off is very nice indeed. In this story, however, the irony lies in the fact that the person who "wins" the lottery loses his or her life in an especially terrible way. As we slowly begin to realize what the lottery is really all about, the horror of the story grows until its final savage conclusion.
The idea of a lottery suggests taking part in a competition or game in which the winner receives a high-value or highly desirable prize. The title of Jacksons's story is, therefore, ironic because, in her lottery, the winner does not receive a prize; she is, in fact, condemned to death. This adds an extra layer of irony because Jackson's winner actually loses the biggest and most desirable prize of all: the gift of life.
By employing such an ironic title, Jackson completely smashes the reader's expectations of the story's events. While she hints at the violence to come (by referring to the stones in the opening paragraphs), the reader does not realize the implications of winning the lottery until the very end of the story when the winner, Tessie Hutchinson, is standing alone in the center of a "cleared space" which is surrounded by residents clutching stones of varying sizes.
the title of this story is ironic because when we see a lottery now days we imagine that if we win then we get something for winning. in the story when someone wins the lottery it is not something that is good and being happy for. In the story the poor lady get stoned, which is something that wouldnt be liked by most people. we expect to win something in a lottery that makes us happy not to hurt us.