Abstract: In the process of promoting agricultural modernisation, the cultivated land landscape fragmentation has seriously hindered the development of agricultural scale. It is of great theoretical and practical significance to scientifically reveal the spatial and temporal patterns of cultivated land landscape fragmentation in China for the formulation of refined cultivated land protection policies, the efficient intensive scale use of cultivated land resources, and the modernisation of agriculture and rural areas. Based on land use remote sensing data, this study calculated the patch density, edge density, landscape shape index, mean patch area, mean fractal dimension index, landscape division index, splitting index, and agglomeration index of cultivated land of county in 1980, 1990, 2000, 2010 and 2020. The cultivated land landscape pattern indices of each county were weighted and summed to obtain the cultivated land fragmentation index (CFI) using principal component analysis. Kernel density analysis was then used to characterize changes in the CFI across the country and within each agricultural region. Finally, its influencing factors were analysed with the help of geographically weighted regression models. The results of the study show that: (1) From 1980 to 2020, the national average values of the CFI were 5.544, 5.546, 5.567, 5.619, and 5.669, respectively. The CFI was lower in the Northeast Plain, the North China Plain, the Middle and Lower reaches of the Yangtze River and the Sichuan Basin, while it was higher in the Loess Plateau, the Southeast Hills, the East of the Yunnan-Guizhou Plateau, the Qinling Mountains, and the Daba Mountains. The CFI in the Loess Plateau, the Southeast Hills, the eastern part of the Yunnan-Guizhou Plateau, the Qinling Mountains, and the Daba Mountains is higher. During the study period, 80.47% of the county units had an increase in the CFI.(2) The CFI in counties nationwide has been increasing as a whole, and the gap between regions in the CFI has been gradually narrowing. Except for the Qinghai Tibet Plateau, Northern arid and semiarid region and Northeast China Plain, the overall trend of CFI in other regions increased from 1980 to 2020. (3) From 1980 to 2020, the county units with the decrease of cultivated land area and the increase of CFI accounted for the highest proportion. Most of the county units with a decrease in cultivated land area were distributed south of the Hu Huanyong line, and most of the county units with an increase in cultivated land area were distributed between the first and second terraces. (4) The average elevation, distance from prefecture-level cities and annual precipitation mainly had positive effects on CFI. The effects of the percentage of construction land, population density and GDP on CFI showed spatial heterogeneity, and along with socio-economic development, these factors played different roles in influencing the CFI at different stages. In the future, China's cultivated land needs to focus on optimising patterns. The management of cultivated land fragmentation at the county scale needs to be based on the principle of adapting to local conditions, drawing on the management models of different regions, and achieving diversified participation, co-ordination and dialectical management.