Abstract: Promoting the standardization of farmland circulation and encouraging both parties involved in farmland circulation to sign formal contracts are important guarantees for achieving moderate-scale agricultural operations. However, in practice, farmland circulation is still dominated by informal contracts, which is not conducive to the efficient allocation of farmland resources. Based on survey data from 1,198 rural households in Jiangxi Province, this study empirically examines the impact of high-standard farmland construction on farmers’ choice of farmland circulation contracts and its underlying mechanisms. The results show that: 1) high-standard farmland construction significantly increases the probability of farmers choosing formal contracts, and this conclusion remains robust after addressing endogeneity concerns and conducting multiple robustness checks. 2)high-standard farmland construction promotes the adoption of formal contracts through four channels: reducing farmland fragmentation, increasing land transfer rent, expanding the scale of land transfer, and facilitating transfers among non-acquaintances. 3) the impact of high-standard farmland construction on contract choice exhibits significant heterogeneity in terms of operational scale and property rights conditions, with stronger effects observed among households with larger transferred-in land areas and those that have completed land certification. Based on these findings, it is necessary to promote the coordinated development of high-standard farmland construction and contract standardization, implement differentiated policies according to operational scale and property rights conditions, and further strengthen the protection of property rights institutions, thereby providing institutional support for the standardized and efficient operation of the farmland transfer market.