Urban agglomeration is an important growth pole for China's future economic development. In recent years, the national high level has paid more and more attention to supporting the development of various urban agglomerations in China. As the third-largest urban agglomeration in China, the Beijing-Tianjin-Hebei urban agglomeration is led by Beijing and Tianjin and develops together with 11 prefecture-level cities in Hebei Province. However, the gap between the top two Yangtze River Delta and Pearl River Delta urban agglomerations is still not small. Meanwhile, the gap between different cities within the Beijing-Tianjin-Hebei urban agglomeration has always been considerable, and the coordinated development of each city is less effective than that of the other two urban agglomerations. This paper first calculates the compactness index to obtain the changes in the compactness of the Beijing-Tianjin-Hebei region from 2013 to 2019 and analyzes the development trend of the region in recent years. Among them, the compactness of space is growing rapidly, and the growth rate of industrial compactness and traffic compactness is relatively slow. It is based on identifying the core area of the urban agglomeration based on population density. We put forward ideas on achieving better coordinated regional developments and accelerating integrations.