The coding rules of tax registration number are as follows: taxpayer identification number refers to tax registration number (branch organization code and ID card registration);

1. The tax registration certificate number consists of 6 administrative division codes and 9 organization codes.

The organization code is the nine digits on the organization code certificate issued by the Bureau of Quality and Technical Supervision, and this combination of digits is unique.

2. The reasons for individual operators to apply for tax registration certificates are: the old ID card 15 digits plus five zeros or the new ID card 18 digits plus two zeros;

If multiple households use the same ID card for tax registration, the last two digits of the second household's tax registration certificate will be changed to "0 1" and the third household will be changed to "02".