1 and 1-3 digits: it is one of the country codes of China. (690-695 are all codes of Chinese mainland, which are used internationally).

2. 4th-8th digits: * * 5th digit, representing the manufacturer code, which is applied by the manufacturer and allocated by the state.

3. No.9-12: * * * 4, which represents the commodity code in the factory and is determined by the manufacturer.

4. Bit13: * * *1,which is a check code, is calculated from the previous bit 12 according to a certain algorithm.

At present, the commonly used coding systems in the world are EAN barcode, UPC barcode, 25 barcode, cross barcode, Kudba barcode, Sanjiu barcode and 128 barcode, and the most commonly used commodity is EAN commodity barcode.

EAN commodity bar code, also known as general commodity bar code, is formulated by ean international and is widely used in the world. It is the most widely used commodity bar code in the world. This kind of barcode is also widely used in China. EAN commodity bar codes are divided into EAN- 13 (standard version) and EAN-8 (abbreviated version).

The coding of commodity bar codes follows the principle of uniqueness, so as to ensure that commodity bar codes will not be repeated in the global scope, that is, a commodity item can only have one code, or a code can only identify one commodity item. Commodities with different specifications, different packages, different varieties, different prices and different colors can only use different commodity codes.