1. Rent-and-Yong tune production was a formal national tax system in the early Tang Dynasty, which had system defects and implementation drawbacks.

2. Mainly manifested in the following aspects: First, with the development and changes of society, the tenancy regulation system and the land equalization system are increasingly out of touch, and the material basis for tax collection and regulation is gradually lost.

3. Second, the rent adjustment tax has been fixed and rigid for a long time and cannot adapt to the new situation of social and economic development.

4. Third, the continuous loss of household registration leads to the continuous loss of taxpayers, which leads to the continuous narrowing of the tax base for rent adjustment.

5. It is the widespread tax evasion that is disintegrating day by day, undermining the effective implementation of the rent adjustment system.