In this study, to apply the new policy of 「Preliminary Research on Weapon System Performance Improvement at Depot Maintenance」 in accordance with the revision of 'Total Lifecycle Management Regulation' of the Ministry of National Defense, a pilot project was conducted on the K56 ammunition carrier, with depot maintenance scheduled at OOOO. During the project period, the improvement requirements were collected and categorized into six groups; ① improving performance, ② resolving issue of obsolescent/discontinued parts, ③ applying engineering changes, ④ applying advanced technologies, ⑤ resolving repetitive defects, and ⑥ applying parts localization. For each improvement requirement, technical feasibility and impact on the weapon system were reviewed. To prioritize the improvement requirements, the Delphi technique and Analytic Hierarchy Process (AHP) were applied to establish the quantitative evaluation items and their respective weights based on discussion with military experts. Based on the established evaluation criteria, the improvement requirements were then evaluated and prioritized by the Armed Forces. To further verify the prioritization result, the ranking of the requirements was reviewed by the industry, academy, and military experts, and finalized to complete the pilot project of preliminary research of K56 ammunition carrier performance improvement.