Integration refers to the integration of three or more cities, mostly two cities. Urbanization is more the natural development structure of urbanization process, while integration needs administrative guidance.

There is no obvious boundary between cities in the same city, and there will be a certain distance between the main urban areas of integrated cities, but they cooperate with each other in urban division of labor and industrial layout.

Cities that shout the slogan of integration are generally far away from the main city, and urbanization cannot cover the distant and huge rural areas between them, but they are closely related in industrial layout, or there is a relationship between upstream and downstream supply chains, which is inseparable in industrial development.

For example, Beijing-Tianjin-Tangshan integration, Beijing focuses on developing finance, internet and high-tech industries, Tianjin develops port economy and assumes the role of regional logistics center. Tangshan mainly undertakes industrial spillover from Beijing, assists Beijing's industrial upgrading, and at the same time improves its own industrial structure to form an integrated city with perfect division of labor between Beijing, Tianjin and Tangshan.