Adventures of Huckleberry Finn is one of the most greatest works of Mark Twain, an American literary giant in the 19th century, telling the story of fleeing and seeking for freedom along the Mississippi river. This paper will use the theory of core-pe-riphery to analyze the encounter and mutual-helping of Huck and Jim.Their adventures reflect the fate of marginal characters, dis-close some problems covered in the marginal spaces and make some marginal voices heard. What reflected behind is that the true, the good, and the beautiful of human nature and the righteousness of society are never absent.