The agricultural land management under the household responsibility system (HRS) in rural China empowers farmers with land tenure rights, meeting the basic needs for their livelihoods and employment by cultivating the land. This paper investigates the pivotal role of agricultural cultivated land as a social safety net, ensuring livelihood security for farmers confronting a recession in off-farm employment. Our analysis is based on data collected from six provinces (Heilongjiang, Henan, Zhejiang, Yunnan, Shandong, and Anhui) in the rural areas of China from 2019 to 2020. We investigated the impact of the off-farm employment recession on the mental health of farmers and the moderating effect of land as a social safety net on the relationship between the off-farm employment recession and mental health. The analysis points to the following results: (1) The majority of farmers have significantly reduced off-farm working time during employment recession. (2) The off-farm employment recession has worsened farmers’ mental health. (3) Farmers’ land assets through tenure rights provide both income and employment security functions, which can mitigate the adverse effects of the off-farm employment recession on their mental health. The findings of this study highlight the crucial role of land assets to reduce the negative impact of unemployment in the context of economic recession, emphasizing the significance of the policies supporting the land rights among vulnerable rural groups.