Legal analysis: the taxpayer identification number is the number on the tax registration certificate, usually referred to as the tax number. After the integration of the three certificates, the taxpayer identification number and the unified social credit code are the same number, which is represented by 18 Arabic numerals or capital English letters. According to the standard, the unified social credit code is represented by 18 Arabic numerals or capital English letters, namely 1 registration management department code, 1 organization category code, 6-digit registration management administrative division code, 9-digit subject identification code and 1 check code.

Legal basis: Article 9 of the Individual Income Tax Law of People's Republic of China (PRC) takes the income as the taxpayer and the unit or individual that pays the income as the withholding agent. If the taxpayer has a China citizenship number, the China citizenship number shall be the taxpayer identification number; If a taxpayer does not have a China citizenship number, the tax authorities shall issue a taxpayer identification number. When a withholding agent withholds tax, the taxpayer shall provide the withholding agent with the taxpayer identification number.