The Domain Name System (DNS) is designed to be distributed, which aims to provide services with low latency and great reliability. However, after decades of development and changes in Internet business models, various aspects of the DNS ecosystem have begun to show signs of centralization. To investigate the centralization from the viewpoint of hosting service providers, we develop an automated method based on similarity among NS domains and co-hosting relationship to identify the hosting providers for authoritative name servers, so that we can identify hosting providers in DNS zone file to count the number of domains which a hosting provider host. This tool demonstrates greater accuracy than previous methods and our testing demonstrates the ability to identify hosting service providers for most domains in real-world measurement tasks. Using this tool, we conducted measurements on the dataset combined with .com, .net and .org TLD zones. We find that the top 10 providers collectively host over 54.19% of domains while top 100 providers host over 82.99% domains, which shows a significant level of centralization in hosting service providers within the DNS. Through an analysis of NSone’s NS domains and a statistical examination of top providers’ NS domains, we find that directly identifying the base domain as the provider is inappropriate. Furthermore, we discover relationships among hosting providers and between hosting providers and infrastructure that are more complex than previously anticipated. Finally, based on our research findings, we offer corresponding suggestions to mitigate the continued development of centralization.