Abstract: As the core guarantee zones of China’s national food security strategy, major grain-producing areas play a crucial role in ensuring national food resilience. Understanding the spatiotemporal dynamics and driving mechanisms of food security resilience in these regions is vital for achieving the goal of building a strong agricultural sector and promoting sustainable rural development. Based on statistical data from China’s major grain-producing regions from 2000 to 2020, this study constructed a food security resilience evaluation index system that encompasses the resilience of the grain industrial chain, supply chain, and value chain, grounded in resistance, adaptability, and transformation capacity. Specifically, the entropy method was employed to quantify the resilience levels of the industrial chain, supply chain and value chain (Three-Chain) in food security, while a coupling coordination model was applied to measure their synergy. Kernel density estimation was used to examine absolute differences and variation characteristics. Furthermore, the contribution of subsystem indicators was ranked by the random forest algorithm, identifying nine key factors with significant importance, and the geographical detector method was employed to interpret their driving effects on food security resilience. The results indicate that: (1) From 2000 to 2020, the resilience indices of the grain industrial chain, supply chain, and value chain in major grain-producing regions increased by 0.179, 0.253, and 0.140, respectively. Heilongjiang Province exhibited the highest average growth rates for industrial and supply chain resilience, respectively, while Jiangsu Province showed the highest growth rate for value chain resilience. In contrast, the resilience levels of the "three-chain" in Jilin and Liaoning Provinces increased at a lower rate, with industrial chain resilience rising from 0.079 and 0.109 to 0.191 and 0.183, respectively, and supply chain resilience increasing by 0.162 and 0.119. (2) During the same period, the coupling coordination degree of food security resilience rose from 0.370 to 0.571, shifting from mild imbalance to forced coordination. Shandong Province and Jiangsu Province exhibited relatively high coupling coordination, reaching intermediate coordination level, whereas Inner Mongolia, Jilin, and Liaoning remained on the near imbalance. (3) The overall coordination level of the three-chain in food security resilience has continuously improved, with substantial inter-provincial disparities in the early study period gradually narrowing over time, trending toward equilibrium but without a universal convergence trend. (4) Among subsystems, value chain resilience factors had a greater driving effect on the coordination of the three-chain than supply chain and industrial chain resilience factors. At the individual factor level, the gross output value of agriculture, forestry, animal husbandry, and fishery, as well as general public budget revenue, were identified as the key influencing factors for the coordination of the three-chain, which was also affected by multi-factor interactions. (5) The coordination level of food security resilience in Liaoning, Jilin, and Inner Mongolia remains relatively low, necessitating a clear identification of weaknesses in the resilience of the three-chain and the implementation of region-specific and time-specific development strategies. The findings provide decision-making references for enhancing food security resilience in major grain-producing regions and contribute to establishing a new food security framework characterized by deep coordination among the ‘three-chain’ in China’s major grain-producing areas.