Originally, there were seven top-level domain names by organization: com (commercial organization), net (network service organization), gov (government organization), mil (military organization), org (non-profit organization), edu (education department) and int (international organization). 1997 added seven top-level standard domain names: firm (enterprise and company), store (commercial enterprise), web (entity engaged in web-related business), arts (entity engaged in culture and entertainment), REC (entity engaged in leisure and entertainment), info (entity engaged in information service) and nom (individual engaged in personal activities and publishing personal information). The registration service of these domain names is undertaken by many institutions, and CNNIC is also fortunate to be one of the registration institutions; According to ISO-3 166 standard, national domain names are generally run by NIC (Network Information Center) in various countries.

Geographically, the top domain names are AQ (Antarctica), AR (Argentina), AT (AUstria), Au (Australia), BE (Belgium), BR (Brazil), ca (Canada), CH (Switzerland), CN (China), DE (Germany), DK (Denmark) and es (Denmark). IS (Iceland), IT (Italy), JP (Japan), KR (Korea), MY (Malaysia), NL (Netherlands), NO (Norway), NZ (new Zealand), PT (Portugal), RU (Russia), SE (Sweden), SG (Singapore) and th (Thailand).

The domain name system in China is divided into two groups: category domain name and administrative domain name. There are six kinds of domain names, which are divided into: A C-scientific research institutions; COM-major in engineering, business and finance; EDU-educational institutions; GOV-government departments; Network-information center and operation center of internet and access network; ORG-various non-profit organizations. Administrative domain names are divided according to the administrative regions in China, and the division standards are determined according to the national standards issued by the State Bureau of Technical Supervision, among which 34 "administrative domain names" are applicable to all provinces, autonomous regions and municipalities directly under the Central Government, namely: BJ- Beijing; SH- Shanghai; TJ- Tianjin; CQ- Chongqing; He-Hebei Province; Sx- Shanxi province; Nm- Inner Mongolia Autonomous Region; Ln-Liaoning province; JL- Jilin Province; HL- Heilongjiang Province; Js- Jiangsu province; ZJ- Zhejiang Province; Ah-Anhui; FJ- Fujian province; JX- Jiangxi Province; SD- Shandong Province; Ha-Henan province; H b- Hubei province; HN- Hunan Province; GD- Guangdong Province; GX- Guangxi Zhuang Autonomous Region; Hi-Hainan Province; SC- Sichuan Province; Guangzhou-Guizhou Province; Yn-Yunnan province; XZ- Xizang Autonomous Region; Sn- Shaanxi province; GS- Gansu province; Qh- Qinghai province; NX- Ningxia Hui Autonomous Region; XJ- Xinjiang Uygur Autonomous Region; Tw- Taiwan Province Province; Hong Kong-Hong Kong; Macau mo. CN domain name is managed by CernNic, except edu.cn.

The traditional domain name and website address is a technical problem with strict regulations. The above parts constitute a complete "website", and some websites also include databases, passwords and other contents. Recently, Chinese domain names have appeared, such as "372 1 Chinese website", which is an "application and service" based on IP address and domain name technology. It does not need to change the existing network structure and domain name system, but transforms a complex website into an intuitive Chinese vocabulary, so that China users can surf the Internet easily. Another kind of "CNNIC Chinese domain name" highlights the concept and technology of the network, because it is a technical standard and specification, and its introduction makes the localization of domain names have a standard to follow, which fully embodies the identity of CNNIC as the domain name management organization in China and provides localization for Chinese websites.