The Significant Changes of Land Systems——A Case Study of the Average-land System in the North Wei Dynasty

In the process of transition from tribal-clan to feudal society,the average-land system occurred in the North Wei Dynasty,which checked annexation of land to a certain extent.It not only inherited the landlord class' absolute ownership of the land,but also permited the conditional free land sale in a certain range,which was the legal form of feudal ownership of land.