Abstract: Personal income taxation reform did not achieve substantial progress after more than twenty years，which goal is to establish a tax system that combines taxonomy with classification. The fundamental reason is that we use the tax model as the standard of personal income tax legal system，which leads to uncertainty in the objectives of the reform. The inherent characteristics that Unity，objectivity and certainty of the constitutive elements of taxation provides a useful idea for the refinement and clarity of its reform objectives. The advancement of reform goals of personal income taxation should adhere to the premise of the statutory，completeness and definitude of tax constituent elements，and then distinguish the impact of the tax system on its constituent elements. Accordingly，we improve firstly the tax identity judgment rules，tax object definition method，tax object attribution rules，and tax rate. And then consider the degree of “synthesis” of tax system to design of taxation unit，tax structure，tax base deduction.