The Water Margins was one of the four famous Chinese classical novels. It told the story of 108 rebel leaders at the end of the Northern Song Dynasty. Although the theme of the novel was about the righteous thief, there were also some elements that explored human nature, society, politics, and so on. The theme of the novel was 'The Way of Loyalty.' The author expressed the theme of "loyalty" by describing the lives and struggles of the righteous thieves. He believed that loyalty was the most basic value of human society and an important indicator of whether a person had a conscience and moral standards. The novel emphasized their determination and perseverance to fight for "loyalty" by describing the mental journey of Song Jiang, Lu Junyi and other rebel leaders. At the same time, it also showed the good and evil sides of human nature. In addition, Water Margins also discussed social and political elements. The novel depicted the social reality of the late Northern Song Dynasty and revealed the problems of the official thief family and class contradictions. Through describing the backgrounds and personalities of the leaders of the rebels, the author shows the contradictions and struggles between different classes of people, and also reveals some drawbacks and problems of the feudal society. The theme of Water Margins was "The Way of Loyalty", which was expressed by describing the lives and struggles of the righteous thieves. At the same time, the novel also explored social and political elements to show the good and evil sides of human nature.