Expropriation and occupation of croplands are essential in protecting land quantity during rapid urbanization, and so is reducing cropland abandonment during agricultural production; therefore, it deserves close attention. In this regard, this chapter utilizes nationally representative panel data from the 2017 and 2019 China Rural Household Panel Survey (CRHPS), and staggered difference-in-differences (DID) model, to explore how the land tenure reform helps in protecting land quantity during agricultural production by estimating the influence of land certification on cropland abandonment, its mechanisms, and its heterogeneous effects among groups at the provincial, community, and household levels. Results show that land certification significantly contributes to the protection of land quantity during agricultural production, and it reduces the area of abandoned croplands by at least 4%. This effect is mainly achieved by improving soil fertility, promoting land transfer, increasing the availability of agricultural subsidies, and raising agricultural income. However, while land certification benefits farmers in non-major grain-producing areas and western regions, in plain, remote, and non-politically central villages, and farmers who have not undergone land transfer or land adjustment, it is not beneficial for others. This study enriches the applicability of the property rights theory in the Chinese context, and provides Chinese evidence for other developing countries to strengthen the protection of land quantity, by deepening the reform of the land tenure system under different circumstances.