Legal analysis: Mortgage interest tax credit refers to the interest expense of the house mortgage of the purchaser, which can be used as pre-tax deduction. Generally speaking, when calculating the monthly personal income tax payable, mortgage interest is deducted from the income tax payable such as wages and salaries, and the rest is calculated as tax. Personal income tax after the New Deal = taxable income (salary income-five insurances and one fund-mortgage interest) × tax rate-quick deduction.

Legal basis: Individual Income Tax Law of People's Republic of China (PRC).

Article 2 Individual income tax shall be paid on the following personal income:

(1) Income from wages and salaries.

(2) Income from remuneration for labor services;

(3) Income from remuneration;

(4) Income from royalties;

5. Operating income.

(6) Income from interest, dividends and bonuses;

(7) Income from property lease;

(8) Income from property transfer;

(9) Accidental income.

Individual income tax shall be calculated on a consolidated basis in the tax year in which individual residents obtain income from items 1 to 4 of the preceding paragraph (hereinafter referred to as comprehensive income); Non-resident individuals who obtain income from items 1 to 4 of the preceding paragraph shall calculate individual income tax on a monthly or itemized basis. Taxpayers who obtain income from items 5 to 9 of the preceding paragraph shall calculate individual income tax separately in accordance with the provisions of this law.

Article 8 Under any of the following circumstances, the tax authorities have the right to make tax adjustments in a reasonable way:

(1) The business dealings between individuals and their related parties do not conform to the principle of independent transactions, and there is no justifiable reason to reduce the tax payable by individuals or their related parties;

(2) Enterprises controlled by individual residents established in countries (regions) where the actual tax burden is obviously low, or enterprises jointly controlled by individual residents and enterprise residents, do not distribute or reduce the profits belonging to individual residents without reasonable business needs;

(three) individuals obtain improper tax benefits by implementing other arrangements that do not have reasonable commercial purposes.

If the tax authorities need to pay back the tax in accordance with the provisions of the preceding paragraph, they shall pay back the tax according to law and charge interest.