Due to the threshold of academic qualifications under the "competition for talents", the labor force structure brought by the settlement policy of big cities in China has gradually changed from the traditional urban-rural dual structure to a new ternary structure composed of local labor force, high-quality foreign labor force and ordinary foreign labor force, so as to enhance the precise attraction and internal attraction of high-quality foreign talents. In China, there have been studies on the household registration system based on the traditional urban-rural dual structure, which explored the restriction of household registration system barriers on the scale of cities during the migration of farmers from rural to urban areas. However, the direct influence of the differential household registration system on heterogeneous foreign labor force, and the indirect impact on urban planning system is less considered. Therefore, this paper expands the traditional dual structure composed of local residents and foreign immigrants into a new ternary structure composed of local residents, high-quality foreign labor force and ordinary foreign labor force. Taking the Yangtze River Delta urban agglomeration as an example, this paper discusses how the threshold of different academic qualifications will affect the internal interaction of heterogeneous labor and the city scale hierarchy, and put forward reasonable suggestions for the integrated development of the Yangtze River Delta urban agglomeration.
