Abstract: Cultivated land abandonment has become a significant land use issue affecting China's food security. Under the current production structure where large-scale farmers and smallholder farms coexist, the external economies of scale generated by the development of large-scale farmers can influence other agricultural producers within the region, thereby presenting new opportunities to mitigate cultivated land abandonment. Using data from the 2020 China Rural Revitalization Survey, this study adopts an exogenous perspective and employs methods such as 2SLS and IV-Probit to empirically examine the impact of the development of large-scale farmers on smallholder cultivated land abandonment behaviors and their underlying mechanisms. It further analyzes heterogeneous effects across different characteristics. The findings reveal: 1) In the sample, 4.21% of arable land was abandoned, with 9.25% of households engaging in abandonment behaviors, averaging 0.42 mu of abandoned cultivated land per household. large-scale farmers accounted for an average of 2.71% of all farmers. 2) An increase in the proportion of large-scale farmers within a region significantly suppresses both the proportion of abandoned cultivated land among smallholder and their decision to abandon cultivated land. This effect is achieved through two pathways: land transfer and the purchase of agricultural socialized services. 3) Topographical differences, differentiation differences, and generational factors partially influence the role of large-scale farmer development in shaping smallholder cultivated land abandonment behaviors within a region. Compared to farmers in plains areas, non-agricultural farmers, middle-generation farmers, and older-generation farmers, the increase in the proportion of large-scale farming households within a region exerts a more pronounced inhibitory effect on the proportion of abandoned cultivated land and the decision to abandon cultivated land among farmers in hilly and mountainous areas, part-time farmers, full-time farmers, and younger-generation farmers. Therefore, to effectively curb the trend of cultivated land abandonment and safeguard national food security, the government should further refine land transfer mechanisms and socialized service support systems, strengthen publicity, guidance, and technical training, and implement differentiated incentive measures. This will create a favorable institutional environment for large-scale agricultural operations, fully leverage the demonstration effect of large-scale farmers, effectively integrate smallholder into modern agricultural development, and foster a virtuous cycle of mutual development.