On March 2, 2018, the Ministry of Industry and Information Technology (MIIT) issued an announcement to adjust the Chinese internet domain name system, which came into effect on the day of the announcement. Under the national top-level domain ".CN," two types of second-level domains were established: "Category Domains" and "Administrative Region Domains."

I. Establishment of "Category Domains," which includes 9 categories:
1. "政务" (Government): Applicable to party, government, and various levels of government departments.
2. "公益" (Public Welfare): Applicable to non-profit organizations.
3. "GOV": Applicable to government agencies.
4. "ORG": Applicable to non-profit organizations.
5. "AC": Applicable to scientific research institutions.
6. "COM": Applicable to enterprises in industries such as commerce and finance.
7. "EDU": Applicable to educational institutions.
8. "MIL": Applicable to national defense agencies.
9. "NET": Applicable to organizations providing internet services.
II. Establishment of "Administrative Region Domains," totaling 34:
Administrative region domains are divided based on China's administrative divisions, with standards determined according to national standards published by the former National Technical Supervision Bureau. These administrative region domains are applicable to China's provinces, autonomous regions, and municipalities directly under the central government. They are as follows:
1. "BJ" Beijing Municipality
2. "SH" Shanghai Municipality
3. "TJ" Tianjin Municipality
4. "CQ" Chongqing Municipality
5. "HE" Hebei Province
6. "SX" Shanxi Province
7. "NM" Inner Mongolia Autonomous Region
8. "LN" Liaoning Province
9. "JL" Jilin Province
10. "HL" Heilongjiang Province
11. "JS" Jiangsu Province
12. "ZJ" Zhejiang Province
13. "AH" Anhui Province
14. "FJ" Fujian Province
15. "JX" Jiangxi Province
16. "SD" Shandong Province
17. "HA" Henan Province
18. "HB" Hubei Province
19. "HN" Hunan Province
20. "GD" Guangdong Province
21. "GX" Guangxi Zhuang Autonomous Region
22. "HI" Hainan Province
23. "SC" Sichuan Province
24. "GZ" Guizhou Province
25. "YN" Yunnan Province
26. "XZ" Tibet Autonomous Region
27. "SN" Shaanxi Province
28. "GS" Gansu Province
29. "QH" Qinghai Province
30. "NX" Ningxia Hui Autonomous Region
31. "XJ" Xinjiang Uygur Autonomous Region
32. "TW" Taiwan Province
33. "HK" Hong Kong Special Administrative Region
34. "MO" Macao Special Administrative Region