May 20 is the 23rd Word Metrology Day. The International Bureau of Weights and Measures (BIPM) and The International Organization of Legal Metrology (OIML) released the theme of this year’s World Metrology Day — "Metrology in the Digital Era", in order to acknowledge people of how digital technologies change nowadays world. In response to this international activity, State Administration for Market Regulation settles the Chinese version of the theme.

The World Metrology Day is set up to mark the date to sign the Metre Convention, which is the basis of a globally united measurement system. As a big event of standardization, it supports the scientific research, innovation, manufacture, international trade, life quality promotion and environment conservation.