China's urban agglomeration is not only crucial to tackle with the more and more contradiction between population, resources and environment, but also an important spatial actor to increase the global competitiveness and promote the transformation of China's economic development mode. In the national "14th Five-Year Plan" in 2021, it is proposed to "promote the coordinated and development of large, medium-sized and small cities and towns based on urban agglomeration and metropolitan area". Generally, 19 urban agglomerations designated in this Plan are heterogeneous in development level and national functions. To this end, from the nature of urban agglomerations, especially on agglomeration economy and functional urban region hypothesis, the research focuses on the spatial pattern and changes of these 19 areas mainly based on the 6th and 7th national census. The findings show that, China’s UAs are unique in driving forces, and spatial patterns as well. China’s UAs are more state-led, though now the marketing forces more and more crucial. The UAs have been evolved from the early planned economy period to the reform and opening up period, and then to the further development of the Socialist market economy until now. Unlike other typical UAs abroad, most of the developed UAs are more specialized in manufacture, not in producer services, though these regions show a remarkable high-end services oriented shift in 2010–2020.