Legal analysis: personal income tax cannot be deducted from mortgage. However, for personal mortgage interest, it can be used as a special additional deduction to deduct the taxable income of individual tax. If taxpayers or their spouses use individual housing loans from commercial banks or housing accumulation funds alone or jointly to purchase housing for themselves or their spouses in China, the interest expenses incurred in their first housing loans can be deducted.

Legal basis: Civil Code of People's Republic of China (PRC).

Article 667 A loan contract is a contract in which the borrower borrows money from the lender, repays the loan at maturity and pays interest.

Article 680 usury is prohibited and the loan interest rate shall not violate the relevant provisions of the state. If there is no agreement on the payment of interest in the loan contract, it shall be deemed that there is no interest. If the loan contract does not specify the payment method of interest, and the parties cannot reach a supplementary agreement, the interest shall be determined according to the local or the parties' trading methods, trading habits, market interest rates and other factors; Loans between natural persons are regarded as interest-free.

Calculation of taxable income in Article 6 of the Individual Income Tax Law of People's Republic of China (PRC);

(1) For the comprehensive income of individual residents, the taxable income shall be the income after deducting expenses of 60,000 yuan, special additional deductions and other deductions determined according to law.

(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 labor remuneration, royalties 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.