“Where to store” is a crucial component of “how to store”. Central grain reserves constitute the backbone of China’s grain reserve security，and the rational spatial allocation determines the capacity for emergency response and the overall level of food security.Based on a supply chain risk management，this study constructs an analytical framework focusing on three key stages affecting reserve efficiency—production，consumption，and transportation.It examines the distribution of central grain reserves across producing regions， their alignment with consumption demand，and their connection with transportation.Drawing on the principles of linear programming，the study calculates the optimal range of reserve depots at which grain reserves reach a balanced state with production，consumption，and transportation. Based on these findings，optimization strategies for the current layout of central grain reserve depots are proposed. At present， there are 890 central grain reserve depots，77% of which are located in major grain-producing regions. Among them， the number of depots in four non-major grain-producing regions falls below the lower bound of the estimated optimal range，while that in four major grain-producing regions exceeds the upper bound. The current layout shows a bias toward producing regions and away from consuming regions，resulting in high operating costs and inefficient rotation channels. Additionally，the focus on rations over corn has weakened the ability to ensure the safety of feed grain supplies. Similarly，an emphasis on reserve rather than circulation has resulted in restrictions on grain movement. To address these issues，the layout of static grain reserve depots should be adjusted in a timely manner in accordance with dynamic changes in grain demand. Policy recommendations include balancing the distribution of reserve depots between major and non-major grain-producing regions，optimizing the structure of reserve grain varieties in line with market demand，and enhancing investments in grain storage and transportation infrastructure to improve transfer efficiency.