Cropland into forest or fruit production has been increasingly promising for non-grain land use in China. Rural land-use patterns have been reshaped to dominate the national food security, ecological sustainability, and regional agriculture. This study aims to investigate the spatiotemporal evolution, regional differentiation, and driving mechanisms of cropland conversion into forest or fruit production in China. Time-series data of land cover were collected from 1990 to 2024. Natural, socio-economic, and locational indicators were integrated for suitability evaluation. GeoDetector and MaxEnt models were employed to analyze spatial differentiation, dominant influencing factors, and regional heterogeneity. Optimization zoning and differentiated strategies were further proposed to support the non-grain cropland use during food production and ecological conservation. The results show that (1) Cropland conversion into forest or fruit production exhibited a stepwise increasing trend from 1990 to 2024, with the total conversion area and rate of 1.4×10⁷ hm² and 7.17%, respectively. Particularly, there was a great increase after 2000. Spatially, the pattern was concentrated in southern China and the northeastern forest regions, especially in the southern coastal and southwestern areas. Forest and fruit production gradually expanded to occupy the conventional grain-production spaces and cropland use patterns in many regions. (2) The spatial differentiation of cropland conversion into forest or fruit production was jointly driven by natural environmental, socio-economic, and locational factors, indicating significant regional heterogeneity. The slope was one of the most influential factors on the national scale. There was a significant positive relationship between the conversion rate and the slope, indicating that sloping cropland was more likely to be transformed into forest or fruit production. Explanatory power was observed for the interactions among factors, indicating that the conversion was shaped by the combined effects of multiple drivers. Regional differences also varied in dominant mechanisms. Natural environmental factors dominate in Southwest and Northeast China, such as topography, temperature, and precipitation. Socio-economic and locational factors were also dominant in South China, while both natural and socio-economic conditions were in the middle and lower reaches of the Yangtze River. (3) Grain-suitable regulation units (1.153 ×10⁴ hm²) were distributed in Southwest China, the middle and lower reaches of the Yangtze River, and South China. Orderly restoration and recultivation were prioritized to retain ecologically important patches where necessary. Ecological retention units (2.52 ×10³ hm²) were concentrated in Southwest China. Ecological protection and eco-friendly land-use patterns, such as agroforestry, should be promoted to balance ecological conservation and the economy. Overall, the findings can provide differentiated strategies for non-grain cropland use and the national food security with ecological sustainability.