 This paper reviews several indices commonly used to analyze the structure of a mega-region, such as weighted degree centrality, hub and authority score, and S-score decomposition. It then applies these indices to the case of Guangdong Province, China, to explore its city hierarchy and spatial structure. The results show that Guangzhou and Shenzhen have the highest node degrees and strength of mobility flows, while the Guangzhou-Dongguan-Shenzhen corridor has been identified as the most connected region by the hub and authority score. Additionally, the comparison between the three indices reveals that each index has its own advantages and disadvantages, thus it is necessary to select the appropriate one according to the study context. This article was authored by Yang Yang, Ji Yu, Run Sha, Yang Zhuang, and others.