Deepening the tax reform is the issue that the society cares most. During the two sessions in 2016, it has made it clear that the next step of tax reform is to establish a classification and comprehensive combination of personal income tax system and its specific scheme is expected to launch in 2017. This paper argues that in the new classification and comprehensive income tax mode, it is of necessity to design to the expense deduction method to match it, namely, “mortgage tax” should be viewed as an important part of to “perfect the deduction before tax”, to establish “basic deduction + special deduction” expense deduction mechanism. In order to solve the problems in the process of mortgage interest tax, it is of significance to draw lessons from foreign experience as well as former similar policies in China, in combination with China’s actual conditions, to put forward concrete implementation plan to use mortgage interest as tax to ensure equitability of taxes.