The deduction ratio of personal income tax loans usually refers to mortgage deduction, and there are two ways: (1) both husband and wife deduct 50% respectively; (2) Deduct 100% from the husband or wife. If the payroll tax deduction conditions are met and both of them belong to the other party's first home loan, you can choose whether to deduct 50% or only deduct 100% of one of them, as long as the husband and wife negotiate.