This study analyzes the quantitaive effect of 155M artillery ammunition procurement from third party countries in the wartime using simulation. First, we study the concept of ammunition supply, procurement plan, transportation plan in the wartime and logistics support from third party countries. We then study the ammunition support possibility from third party countries. Secondly, we make a basic model on the sea-lift from Korea to U.S in the wartime using simulation followed by making comparative models on the sea-lift from Korea to U.S and third party countries. Finally, we analyze models on the completion date of ammunition transportation and the ammunition amount of each operation step. We then execute the sensitivity analysis on the ammunition amount from third party countries. In cocclusion, ammunition prcurement from third party countreis more supply 10% than basic model.