Abstract: Abstract: Land is the carrier of human activities. All kinds of social and economic problems in the process of urbanization can be reflected in land use. A large number of labor force has been transferred from rural areas especially in mountainous areas to cities, which has changed the population distribution pattern and land use pattern in different time and regional systems. The marginalization of cultivated land is a typical land use pattern in mountainous areas, and clarifying the characteristics of land marginalization and its mechanism can be used for reference to realize land capital appreciation and rural revitalization. By employing the survey data about 901 farm households involving 6563 plots in Wulong District and Youyang County in Chongqing City of China in 2012 and 2018 and compilation of agricultural product cost and benefit data from 2007 to 2017, this paper regarded cultivated land as an asset for families and revealed the evolution characteristics of cultivated land asset value in recent years, and a Probit model was constructed to identify the driving forces and explored the driving mechanism of abovementioned phenomena. The results showed that: 1) in recent years, the assets value of cultivated land in the investigated areas kept declining, which was manifested in the fact that the generally cultivated maize per km2 has changed from yield to loss, and the average weighted net yield of major crops has decreased from 1 384.50 yuan per hm2 in 2012 to 252.30 yuan per hm2 in 2018, with a drop of 77.09%. The average rent of cultivated land dropped from 1577.45 yuan/hm2 in 2012 to 361.65 yuan/hm2 in 2018, while the proportion of rent-free land transfer rate from 71.09 % to 82.21 %. It can be seen that the assets value of cultivated land in typical mountainous areas in Chongqing are in the decline stage. (2) Plot size, the distance from the homestead, plot quality and land fragmentation were the important determinants of free-rent land transfer, while the rising opportunity cost of farming was the root cause. The mechanism of devaluation of cultivated land is that urbanization has pushed up labor costs and reduces agricultural profits, and cultivated land assets have devaluated and even abandoned. From the view of cost-benefit analysis, the abandonment of cultivated land in the study area is a normal and rational economic activity for farmers, and the devaluation of cultivated land assets is exactly in line with the original intention of returning farmland to forests. The devalued cultivated land or abandoned land of these assets is conducive to improving the ecological environment of the mountainous areas. At the same time, the idle or abandoned land resources in mountainous areas become relatively rich. The government should reasonably introduce urban capital and fully exploit the land resources in order to realize the land capital appreciation in mountainous areas and develop local economy. Furthermore, the government should stop large-scale land reclamation projects in mountainous areas and appropriately replenish cultivated land through land reclamation to avoid waste of public financial funds and destruction of the ecological environment.