The development of labor market segmentation theory has experienced a process of continuous improvement. Its main schools are job competition theory, dual labor market segmentation theory and radical segmentation theory, among which the dual labor market segmentation theory has the greatest influence. In the late 1960s and early 1970s, Lester C. Thurrow, P. B. doringer, M. J. Piol and others put forward the dual labor market segmentation theory on the basis of the original theory. According to this theory, the labor market is divided into primary and secondary labor markets; The main labor market has high income, stable work, good working conditions, many training opportunities and good promotion mechanism; The secondary labor market has low income, unstable work, poor working conditions, few training opportunities and lack of promotion mechanism; For workers in the main labor market, receiving education and training can increase their income, while for workers in the secondary labor market, receiving education and training has no effect on increasing their income; Moreover, there is less flow between the main labor market and the secondary labor market.