唐朝武德七年(公元624年)四月,为了恢复和发展社会经济,保证租税收入,颁布了“租庸调法”,实行“据丁征税”,即对人丁征收数额相等的税收。在大量自耕农存在的情况下,封建王朝用“租庸调法”来保障租税收入,起了一定作用。但此后,由于政治和军事形势变化,社会动荡,特别是封建剥削阶级的残酷剥削和压迫,自耕农被迫典田卖地,土地日益集中,户口户籍破坏严重,按丁征收的“租庸调法”越来越丧失其存在的基础。德宗建中元年(公元780年),宰 In the 7th year of the Tood of the Tang Dynasty (AD 624), in April, in order to restore and develop the social economy and guarantee the tax revenue, the “Tax Concession Law” was promulgated and the “tax deduction in accordance with” was applied. In the presence of a large number of self-employed farmers, the feudal dynasty played a certain role by using the “rent and transfer method” to protect the tax revenue. Since then, however, due to political and military changes and social unrest, especially the brutal exploitation and oppression of the feudal exploiting class, self-employed farmers have been forced to sell land in the Diantian field, their land has been increasingly concentrated, household registrations have been severely damaged, "Lost more and more basis for its existence. Dezong built in the first year (AD 780), slaughter