Zhou Yexin
China Institute of Innovation and Development, School of Economics and Resource Management, Beijing Normal University
Social capital has expanded the traditional concept of capital and has gradually become a research hotspot across sociology, economics, and political science. It can be divided and defined from three levels: macro social capital, meso social capital and micro social capital. Among them, micro social capital has special significance for studying the flow, employment, and income of labor. Social capital not only promotes the flow of migrant workers but also through the labor market affects their wage income，or the operating income obtained by self-employment.
Social capital can provide employment information for job seekers, reduce transaction costs, improve job search efficiency, enhance trust and add value to other social norms, and compensate for the failure of the labor market. At the same time, it can guarantee the authenticity of employment information, speed up the speed of information search, and have the functions of credit guarantee and invisible insurance, to increase the probability of migrant workers working in cities. Besides, social capital can also affect the wage level of migrant workers by breaking through the institutional barriers of the labor market, promoting the mobility of the labor market, as well as its heterogeneity and rebuilding. Also, it plays a central role in the process of operating or even starting a business after migrant workers enter the city. In China, the role of social capital is even more critical. Human capital factors, such as personal work experience and vocational skills can only function through the relational capital.
The academic community is gradually valuing the mechanism of the role of social capital in the income gap. It can be predicted that in the process of urbanization, the social network of migrant workers with strong homogeneity may gradually differentiate and expand the income gap through the distorted labor market. China's migrant workers reached 242 million in 2010. This large-scale group is the most massive township-city migration process in the history of mankind. In this process, social capital promotes migrant workers to obtain non-agricultural job opportunities and increase income. At the same time, with the advancement of urbanization and marketization, various problems will continue to evolve.