A resilient food trade system is crucial for global food security. The spatiotemporal changes in the trade of four main cereals (soybean, wheat, rice, and maize) and their responses to COVID-19 may serve as an efficient indicator of system resilience but remain underexplored. Using the United Nations Comtrade dataset and the COVID-19 dataset, this paper analyzed the evolution of the Global Trade Network for Four Cereals (GTN4) over 21 years and assessed their trade responses to COVID-19. The findings are as follows: (1) The GTN4 underwent a significant shift after 2019. Between 2000 and 2019, the network steadily expanded in size and became more interconnected, both overall and within groups of developing and developed countries. However, following 2019, its overall accessibility declined, with the extent of deterioration varying between these two groups. (2) COVID-19 influenced the cereal trade in 44–69% of countries, with developed nations exhibiting greater resilience. (3) Wheat exports from Germany, rice from Italy, and maize from the United States demonstrated the highest resilience, while Spain’s soybean trade played a key role in global imports. This research provides new insights into global food security and pandemic resilience, informing sustainable development at the national, group, and global levels.