The work aims to study the factors influencing the layout of field ordnance warehouse and the optimization methods of warehouse layout. The importance of ammunition support site was evaluated in combination with expert scoring method and analytic hierarchy process (EAHP). Field ordnance warehouse layout optimization model was established by comprehensively considering importance of ammunition support site, quantity demanded for ammunition, distance between all the ammunition support sites and other factors. Moreover, the model was solved with immune optimization algorithm. Matlab simulation results showed that it was important to select appropriate original parameters when the immune algorithm was applied to solve the optimized layout of field ordnance warehouse, as such parameters not only affected the algorithm's convergence speed, but also affected the final optimization results. Satisfactory results of optimized layout of field ordnance warehouse are obtained by synthesizing the methods of EAHP and immune algorithm.