The specific proportion of personal income tax deduction for housing loan interest is: before marriage, the housing loan interest expenses of both husband and wife are deducted separately, and after marriage, one of them can be deducted by the purchaser, or both husband and wife can deduct 50% of their respective houses according to the deduction standard. Article 9 of the Individual Income Tax Law stipulates that individual income tax shall be paid by taxpayers, and the unit or individual who pays the income shall be 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.

Legal objectivity:

Calculation of taxable income in Article 6 of the Individual Income Tax Law of People's Republic of China (PRC): (1) The comprehensive income of individual residents, after deducting expenses of 60,000 yuan from the income in each tax year, plus the balance after special additional deductions and other deductions determined according to law, is taxable income. (2) For the income from wages and salaries of non-resident individuals, the taxable income shall be the balance of monthly income after deducting expenses of 5,000 yuan; Income from remuneration for labor services, remuneration for manuscripts and royalties shall be taxed. (3) For operating income, the taxable income shall be the balance of the total income in each tax year after deducting costs, expenses and losses. (four) if the income from property leasing does not exceed 4,000 yuan each time, the 800 yuan shall be deducted; If it exceeds 4,000 yuan, 20% of the expenses will be deducted, and the balance will be taxable income. (5) For the income from property transfer, the taxable income shall be the balance after deducting the original value of the property and reasonable expenses from the income from property transfer. (6) Interest, dividends, bonus income and contingent income shall be limited to the taxable income each time. Income from remuneration for labor services, remuneration for manuscripts and royalties shall be the balance after deducting expenses. The amount of remuneration should be reduced by 70%. Individuals donate their income to public welfare charities such as education, poverty alleviation and poverty alleviation, and the part of the donation that does not exceed 30% of the taxable income declared by taxpayers can be deducted from their taxable income; If the State Council stipulates that donations to charity should be fully deducted before tax, such provisions shall prevail. The special deduction specified in item 1 of the first paragraph of this article includes social insurance premiums such as basic old-age insurance, basic medical insurance, unemployment insurance and housing accumulation fund paid by individual residents in accordance with the scope and standards prescribed by the state; Special additional deductions include children's education, continuing education, medical treatment for serious illness, housing loan interest or housing rent, support for the elderly and other expenses. The specific scope, standards and implementation steps are determined by the State Council and reported to the NPC Standing Committee for the record.