Postal codes in the People's Republic of China (simplified Chinese: ?(); traditional Chinese: ?(); pinyin: ) are postal codes used by China Post for the delivery of letters and goods within mainland China.
China Post uses a six-digit all-numerical system with four tiers: the first tier, composed of the first two digits, show the province, province-equivalent municipality, or autonomous region; the second tier, composed of the third digit, shows the postal zone within the province, municipality or autonomous region; the fourth digit serves as the third tier, which shows the postal office within prefectures or prefecture-level cities; the last two digits are the fourth tier, which indicates the specific mailing area for delivery.
The Republic of China (commonly known as Taiwan), on the other hand, is not under control of the People's Republic of China. Therefore, even though it was assigned official postal codes by China Post, those codes are not in use. ROC's postal bureau, Chunghwa Post, uses a different postal code system. All mails between the PRC and the ROC are treated also as international mails, and mailing to Taiwan from Mainland China actually requires the use of the postal codes set forth by Chunghwa Post. The range 000000-009999 is not in use, because it was originally marked for Taiwan.
Codes starting from 999 are the internal codes used by China Post for handling international (including the SARs and Taiwan) mails, and not used by the general public.
100600 (exact code, not a range) is exclusively for diplomatic and foreign institutions (regardless of actual location in Beijing), with preferential (priority) delivery.
Chongqing also uses post codes starting with "63" before 1997.
Chongqing also uses post codes starting with "64" before 1997.
The following codes are for internal operation only, and not in use by the public