In the history of Chinese urban marginality, three groups of people could be included in the marginalized situation: migrant workers, laid-off workers and yizu. The last one, yizu, just emerged after Dr. Lian Si put forward this concept in 2009. However, various debates arose around this new idea. Two main viewpoints have been built: 1) there is no need to be surprised at this yizu phenomenon; 2) yizu is a serious sociological problem and it should be noticed. Therefore, this paper aims at exploring a better understanding of yizu. According to the investigation of yizu people in Guangzhou and various academic theories, the author shows that yizu is being marginalized by the society seriously. The governmental policies, the lost citizenship and the phenomenon of semi-urbanization caused the emergence of yizu. Some possible solutions are suggested on the basis of the causes: cancelling hukou system, improving education, developing education and enhancing the attraction of developing areas.