Farmland abandonment is a pernicious environmental problem in the world. As farmers are decision-makers with regard to farmland utilization and abandonment, it is the key to study the influencing factors from the farmers' perspective. Using the data from 540 rural households in Sichuan Province, this study analyses the impact of farmers' differentiation on farmland abandonment and further explores the effects of land attachment and generational differences on the above impact. The results show that farmers' differentiation positively affects farmland abandonment. Meanwhile, land attachment is the mediator between farmers' differentiation and farmland abandonment. Among the three dimensions of land attachment, land rootedness and land dependence play the main mediating effect. Moreover, generational differences are the moderator between farmers' differentiation and farmland abandonment. Among the three generations, the differentiation of the middle-aged and the older generation of farmers positively affects farmland abandonment, while the differentiation of the new generation of farmers does not significantly affect farmland abandonment. This study can deepen the understanding of the impact mechanism of farmers' differentiation and farmland abandonment and provide a reference for the formulation and implementation of land policy.