All the earlier Chinese stamps have no serial number. In 1949, China Post began printing the serial number on commemorate stamps and special stamps, and the serial number became one of characteristic of P.R. China stamps. In the past years China has issued more than one thousand stamp sets, but the method of number stamps has been changed many times.

C-series Commemorative stamps and S-series Special stamps (1949/1951 – 1966/1967)
The first C-series stamp set C1 was issued on October 8th 1949 and the last set C124 was issued on March 10th 1967. The first S-series stamp set S1 was issued on October 10th 1951 and the last, S75, was issued in May 10th 1966. The format of C-series and S-series stamp serial numbers is as follows: the Chinese word  is short for , meaning Commemorative and  is short for  meaning Special. For example: 59 shows it's the 59th set of C-series, "4 - 3" means the stamp set has a total of 4 items and this stamp is the 3rd in the set. And you could also find "(123)1967" on the right foot of the stamp, it means this stamp was issued in 1967 and it's the 123rd item of the whole C-series stamps to date. Note: not all C-series and S-series stamps show the year of the issue: C16 and earlier, S5 and earlier have no year marks.

W-series stamps (1967- 1970)
W-series stamps has 19 stamp sets, the first set W1 (Long Live Invincible Mao Zedong Thought) was issued on April 20th, 1967, the last W19 ( Revolutionary Youth) was issued on January 21st 1970. During the Chinese cultural revolution, the numbering of stamps was abolished: there were no serial number marks on the stamps. Subsequently, these 19 stamp sets have been called the W-series.

N-series stamps (stamps with serial numbers) (1970 - 1973)
From August 1st 1970 to January 15th 1973, China issued 95 stamps which were not classed as Commemorative or Special stamps, just numbered with the serial number of issue. Only the serial number and year issued were printed on the stamps, hence they are called the N-series.

J-series stamps and T-series stamps (1974 - 1991)
J-series and T-series stamps were introduced in 1974. The pinyin J (commemorative) and T (special) were added to the number. Stamp set J1 was issued on May 15th 1974 and J185 the last was issued on November 16 1991. T1 was issued on January 1st 1974 and the last set, T168, on September 14th 1991.

Stamps numbered chronologically (1992 - current)
Since 1992, all commemorative and special stamps were numbered chronologically within year of issue and set number. E.g. "1992-1(2-1)T": 1992-1 means it is the first set issued in 1992, the numbers in parenthesis indicate the number and position of stamps in set, and the letter T or J indicates if the stamp is Special or Commemorative.

Regular stamps  (1950 – current)                                     
Regular stamps (called the R-series) had no serial numbers or year markings. The first regular set was issued in 1950 and the last R32-3 was issued in 2021.

Individualised stamps (2002 – current)
In May 2002 the first Z-series stamps were issued (sometimes called ‘Greetings’ stamps). These are Individualised stamps without any year or other identifying number. They have a decorative tag attached to the stamp.

Airmail stamps (1951 – 1957)
Airmail stamps were issued only for airmail and numbered with "A" and the serial number. China total issued two airmail stamp sets, A1, issued on 1st May 1951, and A2, issued on September 10th 1957.

Security overprints (2002 - current)
From September 2002, starting with T-series set 2002-19 (The Yandang Mountain), stamps have been overprinted with an additional alpha-numerical number as part of security. These numbers are easily visible under UV light and relate be the sheet number of the stamps.