The Scarlet Letter makes the American writer Nathaniel Hawthorne known all around the world. There are many aspects worth our consideration in The Scarlet Letter, but one about human nature and moral problems is especially deserving of our discussion. This paper mainly reveals the beauty and ugliness of human nature by analyzing the honesty and hypocrisy of the three leading characters in The Scarlet Letter. Hester Prynne is an honest woman, who bravely admits her love to the young minister Dimmesdale and never cheats her husband Chillingworth. Whereas, honesty and hypocrisy have no clear borderline on Dimmesdale and Chillingworth. Because of atonement, the timid, hypocritical minister surpasses himself and returns to honesty at last, but the once-honest scholar changes himself into Satan due to revenge. The paper mainly tells people that the best policy for man is to be true, honest, and ever ready to show one's worst to the outside world.