After the American Civil War, the South had long been confronted with the three rural issues such as the backward of agriculture production methods, poor peasants, and slow development of rural society. The above-mentioned problems are intertwined with the racial problems in the South, which exacerbate the backwardness and darkness of the South.The African Americans there suffered the most, and they were forced to migrate to other parts of the United States in a large scale. In the 20th century, there were two great migration peaks of African Americans in the United States. Till the 1970s, more than 6 million African Americans had migrated out of the South. The three rural issues of the South were the economic reason for the great migration of African Americans, and the great migration promoted the solution of the three rural issues. It shows that the freedom of immigration is indispensable for solving the three rural issues.